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9 months ago
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 Stackful coroutines in C.
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 * `Task` & `Future` coroutines which can pause, waiting for a future.
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 * `ASleep` an example of pausing `Task`s using `Future`s.
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 * `Generator` coroutines used as generators for loops.
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 * `Coroutine` the base coroutine engine.
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 Your code doesn't need to do anything special to be a coroutine. Only standard, or commonly available libraries are needed.
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 ## Quick Start
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 ### Installing
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 You will need to build & link the code, `coroutine/*.c`, as part of your project, and ensure the headers, `include/*`, are available on your include path.
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 ### Tasks
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 To run `Task`s:
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 #!C
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 #include "coroutine.h"
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 #include "task.h"
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 main(){
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 size_t min_stack_size = 8192 * sizeof(void *);
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 void *res = NULL;
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 bool canceled = Task_Run(min_stack_size, 0, maintask, &param, &res);
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 }
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 `Task_Run` runs tasks, switching between them when the current task waits on an `Future`. `maintask()` is run as a task. The start function for any task looks like this:
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 #!C
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 bool mytask(void *param, void **res){
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 // do your thing here
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 return canceled;
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 }
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 When `Task` returns from its start function, it returns whether it was canceled. Canceled `Task`s are assumed to have not finished what they were doing.
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 Within your main task, create `Task`s and `Task_Await()` them when you want to wait for their result:
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 #!C
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 Task task1;
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 Task_ctor(&task1, min_stack_size, 0, adifferenttask, &task1param);
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 void *result;
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 bool canceled = Task_Await(&task1, &result);
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 Task_dtor(&task1);
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 // use the result
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 When a task needs to wait for something, and wants to allow other tasks to run, it should use a `Future`:
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 #!C
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 Future future;
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 Future_ctor(&future);
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 // pass the future to the background-thing-which-might-take-a-while
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 void *res;
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 bool canceled = Future_Await(&future, &res);
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 Future_dtor(&future);
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 When the background-thing-which-might-take-a-while has a result:
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 #!C
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 Future_SetResult(future, false, result);
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 ### ASleep
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 `ASleep()` needs its own system to be started to work:
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 #!C
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 ASleep_StartSystem()
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 // Run tasks here which may now use ASLeep()
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 ASleep_StopSystem();
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 Note that `ASleep_StartSystem()` / `ASleep_StopSystem()` is only needed once per process.
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 Sleeping in a task:
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 #!C
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 bool mytask(void *param, void **result){
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 ..
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 ASleep(time_to_sleep);
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 ..
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 }
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 ### Generators
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 Your code needs to be in a `Coroutine` to use a `Generator`:
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 #!C
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 void *mycoroutine(void *param){
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 // You can use a Generator here
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 }
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 Coroutine_Run(StackSpace, 0, mycoroutine, NULL, NULL);
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 You will need a generator function:
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 #!C
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 void *yield_my_things(void *param){
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 bool domore = true;
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 // loop/call functions to find more values to yield, and when you have one:
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 domore = Generator_Yield(thing);
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 // .. if domore is false, exit your generator - it is being destructed
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 // not actually used by generators, but this is a useful convention for bubbling
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 // the flag out to calling functions.
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 return (void *)domore;
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 }
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 And to use it:
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 #!C
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 Generator gen;
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 Generator_ctor(&gen, generator_stack_size, yield_my_things, "..");
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 void *thing;
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 while(Generator_Next(&gen, &thing)){
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 // use thing - a value yielded by your generator
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 }
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 Generator_dtor(&gen);
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 ### Coroutines
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 While you can use coroutines directly, it's designed as a system to support more useful patterns, like `Async` and `Generators`.
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 Your coroutine will need to have a start function:
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 #!C
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 void *start(void *param){
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 ...
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 }
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 When there is no coroutine running, start your 'main' coroutine:
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 #!C
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 if (Coroutine_Run(min_stack_size, min_stack_headroom, comain, param, &result)){
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 // handle the failure
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 }
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 Create other coroutines like this:
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 #!C
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 Coroutine *cor = Coroutine_New(min)stack_size, min_stack_headroom, start);
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 When you want a Coroutine to be queued to run:
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 #!C
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 Coroutine_Continue(cor, value, run_early);
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 `value` will be start function's parameter, or the value returned from the yield.
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 Within the Coroutine, to yield a value, and allow other `Coroutine`s to run:
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 #!C
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 void *Coroutine_Yield(value, on_yield, void *me);
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 The on_yield function is called after the coroutine has been 'wait'ed, but before the next coroutine is resumed.
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 ## Prerequisites
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 These libraries rely on as much as possible on C's cross-platform comfort zone. C's standard libraries are used as far as possible, but, as `threads.h` is not usually supported, but `pthread.h` usually is, `pthread.h` has been used.
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 If your system isn't supported directly by coroutine, you should be able to configure it in `cor_platform.c`, `cor_platform.h` and `cor_platform_inc.h`.
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 ## How it Works
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 When you `Coroutine_RunSystem()` the passed-in callback is called within a Coroutine and the stack is now managed by the Coroutine system.
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 The coroutine system divides the C stack into smaller stacks, using one of these smaller stacks for each coroutine. This limits the total stack space for all your coroutines - you may need to consider the stack size of each of your coroutines, and also whether a larger C stack might be needed.
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 Each of your threads has its own stack - the coroutine system can be run, or not, independantly on each thread. For some special cases, you may want to adjust each of your thread's stack sizes depending on how it is used.
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 The C stack memory is managed similarly to a malloc heap. Coroutine stacks are allocated on a first-fit basis, and merged on free. When a coroutine runs, if there's free stack beyond the requested limits, that is added in.
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 When not running:
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 ...|[used stack][unused stack ]| free |...
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 When running:
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 ...|[used stack][unused stack ]|...
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 This means the function called back by `Coroutine_RunSystem()` will have all the stack, and be a Coroutine itself.
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 When your coroutine yields and during `Coroutine_New()`, its stack is trimmed back so that there is free stack to allocate more Coroutines:
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 when running:
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 ...|[used stack][unused stack ]|...
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 When yielded and during `Coroutine_New()`:
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 ...|[used stack][unused stack ]|free |...
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 the two stack size parameters set how much the stack is trimmed back:
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 ...|[used stack][unused stack ]|...
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 ...|<----min_size--------------->|...
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 When trimmed:
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 ...|[used stack][unused stack ]|free |...
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 ...|<----min_size--------------->|...
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 and
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 ...|[used stack][unused stack ]|...
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 <-min_headroom->
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 When trimmed:
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 ...|[used stack][unused stac ]|free |...
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 <-min_headroom->
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 If you want to run your coroutine with a fixed amount of stack, start your coroutine like this:
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 Coroutine_New(stack_size, 0, entry)
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 If you want to monitor your coroutine's stack's headroom and chain as necessary:
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 Coroutine_New(0, headroom_size, entry)
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 ## Style
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 The style is influenced by C++. For example, where possible, a `Something *Something_New(a, b, c)` and `Something_Delete(Something *)` will have corresponding `Somthing_ctor(Somthing *, a, b, c)` and `Something_dtor(Something *)` to initialise and finalise a `Something` on the stack, or within another object. Using `.._ctor()` and `.._dtor()` will be faster as they avoid the `malloc()` and `free()`.
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 #!C
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 Something *oneofthem = Something_New();
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 // use oneofthem
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 Something_Delete(oneofthem);
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 Can be also be done like this, and this will run faster:
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 #!C
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 Something oneofthem;
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 Something_ctor(&oneofthem);
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 // use oneofthem
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 Something_dtor(&oneofthem);
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 The exception is `Coroutine_New()` and `Coroutine_Delete()`. The returned `Coroutine` is somewhere on your thread's stack - its memory is managed by the coroutine system, and is allocated and freed quickly.
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 ## Usage
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 When you are using coroutines or generators:
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 #!C
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 void *myfunc(void *){
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 // your function here
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 }
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 size_t min_size = 8192 * sizeof(void *);
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 size_t min_headroom = 256 * sizeof(void *);
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 if (Coroutine_Run(min_size, min_headroom, myfunc, (void *)myparam, NULL)){
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 // handle the failure
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 }
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 You can make many calls to `Coroutine_Run()` or `Task_Run()`. `Coroutine_Run()` ensures the system is started, and that `myfunc` is called
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 from inside a Coroutine. In paeticular, if the Coroutine system is running and `Coroutine_Run()` is called from inside a coroutine, then `myfunc` is simply called.
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 ## Stack Overruns
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 The C stack is divided into smaller stacks. There's one, the startup stack, to give some room for `start` in `Coroutine_RunSystem` to work, and then each `Coroutine` has its own stack. These have guard markers which are checked to see if the stack has overrun. If there is a stack overrun, the system cannot continue - a message is output and the programe exited. There's a number of ways to avoid this issue:
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 * Use less stack. This is, sometimes, the right advice, especially if the startup stack overruns. The expectation is that very little is done by `start` in `Coroutine_RunSystem`. If your situation needs more doing, you can...
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 * increase the stack size for your `Coroutine`. If your use case is even more demanding, such as if you want 1000s of coroutines (so you need small stack chunks), /and/ some of them can recurse an unknown amount (so you need a deep stack for that `Coroutine`), then you can...
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 * monitor stack headroom, and add another stack chunk if you need to:
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 In this last case you'll need to add some code at key points:
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 #!C
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 void *myfunction(void *param){
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 if (Coroutine_GetStackHeadroom() < MIN_ALLOWED_STACK){
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 void *result;
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 Coroutine_Err err = Coroutine_Chain(min_stack_size, min_stack_headroom, myfunction, param, &result);
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 if (err){
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 // handle failure
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 }
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 return result;
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 }
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 // do everything normally
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 }
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 More realistically:
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 #!C
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 struct myfunctionparams {
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 int a;
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 char *b;
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 struct dog *d;
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 }
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 void *mychain(void *param){
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 struct myfunctionparams *myparams = (struct myfunctionparams *)params;
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 return (void *)myfunction(myparams->a, myparams->b, *myparams->d);
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 }
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 int myfunction(int a, char *b, struct dog d){
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 if (Coroutine_GetStackHeadroom() < MIN_ALLOWED_STACK){
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 struct myfunctionparams params = {
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 a,
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 b,
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 &d
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 };
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 void *result;
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 Coroutine_Err err = Coroutine_Chain(my_stack_size, mychain, &params, &result);
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 if (err){
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 // handle failure
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 }
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 return (int)(intptr_t)result;
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 }
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 }
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 And if you want to panic if the C stack overruns:
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 #!C
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 if (Coroutine_GetStackHeadroom() < MIN_ALLOWED_COROUTINE_STACK){
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 if (Coroutine_HasCoroutinesInFreePool() ||
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 (char *)Coroutine_GetCStackTop() - c_stack_end >= MIN_ALLOWED_C_STACK) {
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 struct myfunctionparams params = {
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 a,
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 b,
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 &d
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 };
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 void *result;
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 if (Coroutine_Chain(my_stack_size, mychain, &params, &result)){
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 // handle failure
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 }
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 return (int)(intptr_t)result;
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 }
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 // panic now
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 }
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 ## Configuring for Your Use Case
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 There's a number of adjustments which you may need to make for your situation. These are, mostly, in `cor_platform.h` and `cor_platform_inc.h`.
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 There's some options in `coroutine.h` which you may need to adjust:
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 COROUTINE_STARTUP_STACK_SIZE
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 : The amount of stack set aside for `start` in `Coroutine_RunSystem()`.
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 COROUTINE_MINIMUM_STACK_SIZE
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 : The minimum stack size you'll ask for. The C stack is managed as a heap. If one of the free blocks in that
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 heap is big enough for your new Coroutine, and has spare, if that spare is too small for a `Coroutine` wanting
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 `COROUTINE_MINIMUM_STACK_SIZE` of stack, then the whole free block is given to your new Coroutine, instead
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 of being split into two.
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 `cor_platform.h` has customisations for your particular use case.
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 _Cor_thread_local
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 : How to declare a variable to be thread local
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 COROUTINE_HAVE_ALLOCA_H
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 : Whether your system can `#incude <alloca.h>`.
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 _Cor_Mutex and related routines
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 : Your system's mutex.
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 _Cor_Realtime_Now
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 : Return a realtime clock value compatible with _Cor_Semaphore_Wait.
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 _Cor_Semaphore and related routines
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 : Semaphores on your system.
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 _Cor_Thread and related routines
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 : Threads on your system.
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 `cor_platform_inc.h` has more customisation for your particular use case, for coroutine.h to use.
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 Coroutine_NS(name)
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 : This allows the `Coroutine_???()` functions to be given a different naming convention.
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 Coroutine_API_FUNC(TYPE)
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 : This allows tagging of functions to be accessible to loaded dlls.
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 # API
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 ## Task & Future
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 The pattern for using async is:
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 #!C
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 bool mymaintask(void *param, void **result){
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 // do your main task things here, like starting more tasks
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 }
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 void *res = NULL;
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 bool canceled = Task_Run(mymaintask, NULL, &res);
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 To create and wait for a task:
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 #!C
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 Task task1;
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 Task_ctor(&task1, asynctask1, &task1param);
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 void *res = NULL;
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 bool canceled = Task_Await(&task1, void **res)
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 Task_dtor(&task1);
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 or, if you prefer new & delete:
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 #!C
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 Task *task1 = Task_New(asynctask1, &task1param);
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 void *res = NULL;
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 bool canceled = Task_Await(task1, void **res)
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 Task_Delete(task1);
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 Inside your task, when there is something to wait for and you want other tasks to run while your task is waiting, you will need a future:
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 #!C
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 Future future;
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 Future_ctor(&future);
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 // keep &future to hand for when the background thing completes
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 bool canceled = Future_Await(&future, NULL);
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 Future_dtor(&future);
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 `Future_New()` and `Future_Delete()` are also available if you prefer that style.
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 Inside the callback when the background thing is complete:
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 #!C
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 // result is a void *
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 Future_SetResult(future, result, false);
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 or, if something went wrong:
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 #!C
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 // exception is a void *
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 Future_SetResult(future, exception, true);
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 Back in the task, you can respond to the future:
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 #!C
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 ... Future_Await has returned
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 if (canceled){
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 // exit quickly - you've been canceled
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 // you could, for example, use the future's result as an exception, or error code here
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 }
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 // carry on - the future's result may be an actual result, that's up to you
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 ##### void Future_ctor(Future *fut)
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 fut
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 : The `Future` being constructed
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 Initialise a future. When you no longer need it, use `Future_dtor()`.
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 ##### Future *Future_New()
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 (returns)
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 : The new future
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 Allocates and initialises a future, When you no longer need it, use `Future_Delete()`.
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 ##### void Future_dtor(Future *fut)
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 fut
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 : The `Future` being destructed
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 Destruct a future previously constructed with `Future_ctor()`.
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 ##### void Future_Delete(Future *fut)
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 fut
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 : The `Future` to be destructed and freed
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 Delete (finalise and free) a future previously new'ed with `Future_New()`
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 ##### void Future_SetResult(Future *fut, bool canceled, void *value)
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 fut
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 : The `Future` whose result is being set
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 canceled
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 : The future's `canceled` setting
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 value
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 : The future's result `value`
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 Set the result of a future. This has an effect only the first time its done, ie a completed future can't be canceled and a canceled future can't be completed. When an `Future` has a result, its watchers are called back.
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 The `value` of a future might be a result if the future completes (when `canceled == false`), or could be some sort of exception value if `canceled == true`. The interpretation of a future's `value` is up to the user - as far as the async system is concerned, it's only a `void *`.
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 ##### bool Future_GetResult(Future *fut, void **res)
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 (returns)
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 : The `canceled` value of the `Future`.
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 res
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 : Where to store the value of the `Future`. This may be `NULL`.
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 Get the result of a future.
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 ##### typedef void (*Future_Watcher)(void *me, Future *fut)
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 A `Future_Watcher` is a callback called when a future has a result. The `me` parameter is the one passed to `Future_AddWatcher()`. `fut` is the future which has just got its result.
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 ##### void Future_AddWatcher(Future *fut, Future_Watcher watcher, void *me)
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 fut
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 : the `Future` to add a watcher to
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 watcher
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 : the callback to call when the `Future` has a result.
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 me
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 : the `me` value to pass to `watcher` when it is called back.
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 Add a watcher (callback) to be called when the future has a result. If the future is already complete, `watcher` is immediately called. The `me` value is passed to the watcher as its `me` parameter. It is assumed that a watcher, identified by the `(watcher, me)` pair, will only be added once.
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 ##### void Future_RemoveWatcher(Future *fut, Future_Watcher watcher, void *me)
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 fut
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 : the `Future` to remove a watcher from
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 watcher
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 : the callback of the watcher to remove.
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 me
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 : the `me` value of the watcher to remove.
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 Remove a watcher from a future. It is not an error if no watcher matching `(watcher, me)` is found - it has probably already been called back.
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 ##### bool Future_Await(Future *fut, void **res)
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 (returns)
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 : whether the `Future` was canceled.
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540
 fut
9 months ago
541
 : The `Future` to wait for.
9 months ago
542
543
 res
544
 : Where to store the `value` of the future when it is has a result. May be `NULL`.
545
9 months ago
546
 The current `Task` is paused until the `Future` has a result. Other `Task`s are run while this one is waiting.
9 months ago
547
9 months ago
548
 ##### typedef bool (*Task_Entry)(void *param, void **res)
9 months ago
549
9 months ago
550
 The entry function to an `Task`.
9 months ago
551
9 months ago
552
 ##### void Task_ctor(Task *tsk, Task_Entry entry, void *param)
9 months ago
553
554
 tsk
555
 : The task to construct.
556
557
 entry
558
 : The entry function for the task.
559
560
 param
561
 : The value for `param` to pass to `entry`.
562
9 months ago
563
 Initialises an `Task`. When you have finished with an `Task` you must finalise it using `Task_dtor()`
9 months ago
564
9 months ago
565
 #!C
9 months ago
566
 Task tsk;
567
 Task_ctor(&tsk, mytask, myparam);
9 months ago
568
 // tsk will run if you wait for a task or future
9 months ago
569
 Task_Await(&tsk, NULL);
570
 Task_dtor(&tsk);
9 months ago
571
9 months ago
572
 ##### Task *Task_New(Task_Entry entry, void *param)
9 months ago
573
574
 (returns)
9 months ago
575
 : The new `Task`.
9 months ago
576
577
 entry
578
 : The entry function for the task.
579
580
 param
581
 : The value for `param` to pass to `entry`.
582
9 months ago
583
 This allocates and initialises a new `Task`. When you have finished with your task, you must `Task_Delete()` it.
9 months ago
584
9 months ago
585
 #!C
9 months ago
586
 Task *tsk = Task_New(mytask, myparam);
9 months ago
587
 // tsk will run if you wait for a task or future
9 months ago
588
 Task_Await(tsk, NULL);
589
 Task_Delete(tsk);
9 months ago
590
9 months ago
591
 ##### void Task_dtor(Task *tsk)
9 months ago
592
593
 tsk
9 months ago
594
 : The `Task` to destruct.
9 months ago
595
9 months ago
596
 This finalises an `Task` you ealier initalised with `Task_ctor()`. It is an error to attempt to destruct a task which is running.
9 months ago
597
9 months ago
598
 #!C
9 months ago
599
 Task tsk;
600
 Task_ctor(&tsk, mytask, myparam);
9 months ago
601
 // use tsk
9 months ago
602
 Task_dtor(&tsk);
9 months ago
603
9 months ago
604
 ##### void Task_Delete(Task *tsk)
9 months ago
605
606
 tsk
9 months ago
607
 : The `Task` to delete.
9 months ago
608
9 months ago
609
 This finalises and frees an `Task` you ealier new'ed with `Task_New()`. It is an error to attempt to delete a task which is running.
9 months ago
610
9 months ago
611
 #!C
9 months ago
612
 Task *tsk = Task_New(mytask, myparam);
9 months ago
613
 // use tsk
9 months ago
614
 Task_Delete(tsk);
9 months ago
615
9 months ago
616
 ##### static inline bool Task_Await(Task *tsk, void **res)
9 months ago
617
618
 (returns)
619
 : Whether the task was canceled.
620
621
 tsk
9 months ago
622
 : The `Task` to wait for.
9 months ago
623
624
 res
9 months ago
625
 : Where to store the `Task`'s value when it finishes. This may be NULL.
9 months ago
626
9 months ago
627
 The current `Task` waits for `tsk` to finish, and returns the result.
9 months ago
628
9 months ago
629
 ##### void Task_Cancel(Task *tsk, void *cancel_value)
9 months ago
630
631
 tsk
632
 : The task to cancel.
633
634
 cancel_value
635
 : The value to set on any future this task waits on.
636
637
 This marks a task as canceled. When that task waits on a future that future will be canceled too, using `cancel_value`.
638
9 months ago
639
 ##### static inline bool Task_IsCanceled(Task *tsk)
9 months ago
640
641
 (returns)
642
 : Whether the task is canceled.
643
644
 tsk
645
 : The task to get its canceled setting from.
646
9 months ago
647
 ##### static inline Future *Task_GetAwaitedFuture(Task *tsk)
9 months ago
648
9 months ago
649
 (returns)
650
 : The future the task is waiting on. May be NULL.
651
652
 tsk
653
 : Teh task to read the future it is waiting on.
654
655
 Return the future a task is waiting on.
656
9 months ago
657
 ##### bool Task_Run(Task_Entry start, void *value, void **res)
9 months ago
658
659
 (returns)
9 months ago
660
 : Whether `start` was canceled.
9 months ago
661
9 months ago
662
 start
663
 : The function to use as the main task.
9 months ago
664
665
 value
9 months ago
666
 : The value to pass to `start`.
9 months ago
667
9 months ago
668
 res
669
 : Where to store the result of `start`.
9 months ago
670
9 months ago
671
 Runs `start` as an `Task`. When `start` returns all other tasks must have been destructed, using `Task_dtor()` or `Task_Delete()`.
9 months ago
672
9 months ago
673
 ## ASleep
9 months ago
674
9 months ago
675
 ##### void ASleep_StartSystem()
9 months ago
676
4 months ago
677
 You must start the `ASleep` system to use it. This needs to happen per process. Once you've finished with `ASleep` you must `ASleep_StopSystem()`.
9 months ago
678
9 months ago
679
 #!C
9 months ago
680
 ASleep_StartSystem();
681
 // Now you can use ASleep() on any thread
682
 ASleep_StopSystem();
9 months ago
683
9 months ago
684
 ##### void ASleep_StopSystem()
9 months ago
685
9 months ago
686
 Call this to stop the `ASleep` system.
9 months ago
687
9 months ago
688
 ##### bool ASleep(float delay, void **value)
9 months ago
689
9 months ago
690
 (returns)
691
 : Whether the task was canceled.
9 months ago
692
9 months ago
693
 delay
694
 : How many seconds to delay for.
9 months ago
695
9 months ago
696
 value
697
 : Where to store the cancellation value. This may be NULL.
9 months ago
698
9 months ago
699
 Sleep for `delay` seconds. `*value` will be set to `NULL` if the sleep is successful, and the `cancel_value` if the task is canceled.
9 months ago
700
9 months ago
701
 ## Generator
9 months ago
17
702
9 months ago
703
 The pattern for a `Generator` is:
704
9 months ago
705
 #### A loop which uses the `Generator
9 months ago
706
9 months ago
707
 #!C
9 months ago
17
708
 Generator gen;
6 months ago
709
 Generator_ctor(&gen, generator_stack_size, mygen, &param);
9 months ago
17
710
9 months ago
711
 void *value;
712
 while(Generator_Next(&gen, &value)){
713
 // use value here
9 months ago
17
714
 }
9 months ago
715
 // value is now the return value from the Generator
716
9 months ago
17
717
 Generator_dtor(&gen);
718
9 months ago
719
 Or:
9 months ago
17
720
9 months ago
721
 #!C
6 months ago
722
 Generator *gen = Generator_New(generator_stack_size, mygen, &param);
9 months ago
17
723
9 months ago
724
 void *value;
725
 while(Generator_Next(gen, &value)){
726
 // use value here
727
 }
9 months ago
17
728
9 months ago
729
 Generator_Delete(gen);
9 months ago
17
730
9 months ago
731
 `Generator`s yield a series of `void *`s - what the `void *`s mean is up to you. `Generator_Next()` returns a `bool` to indicate whether the `Generator` has finished.
6 months ago
732
 The `generator_stack_size` is the stack amount made available to your generator.
9 months ago
17
733
9 months ago
734
 #### A generator function
9 months ago
17
735
9 months ago
736
 #!C
9 months ago
737
 void *mygen(void *param){
738
 bool domore = true;
739
 // The parameter is a pointer to a string of chars
740
 for (char *str = param; *str; ++str) {
741
 // The value yielded is a pointer to a character in the string
742
 domore = Generator_Yield(str);
743
 if (!domore){
744
 break;
745
 }
746
 }
747
748
 return (void *)domore;
9 months ago
17
749
 }
750
9 months ago
751
 The `bool` returned from `Generator_Yield()` indicates whether the generator function should yield more values. When it is `false` the `Generator` is being finalised - your generator function should close files, and release any other resources it has claimed, before exiting.
9 months ago
17
752
6 months ago
753
 ##### void Generator_ctor(Generator *gen, size_t generator_stack_size, void *(*start)(void *), void *param)
9 months ago
17
754
9 months ago
755
 gen
756
 : The `Generator` to construct.
9 months ago
17
757
6 months ago
758
 generator_stack_size
759
 : The amount of stack given to the generator.
760
9 months ago
761
 start
762
 : The function which is the start/entry-point of the `Generator`.
763
764
 param
765
 : The value to pass to `start`.
766
767
 Initialise a `Generator`. When you no longer need the `Generator`, use `Generator_dtor()` to destruct it.
768
9 months ago
769
 #!C
9 months ago
770
 Generator gen;
6 months ago
771
 Generator_ctor(&gen, generator_stack_size, mystart, &params);
9 months ago
17
772
9 months ago
773
 // Generator is used
9 months ago
17
774
9 months ago
775
 // ... later:
776
 Generator_dtor(&gen);
777
6 months ago
778
 ##### Generator *Generator_New(size_t generator_stack_size, void *(*start)(void *), void *param)
9 months ago
779
6 months ago
780
 generator_stack_size
781
 : The amount of stack to give to the generator.
782
9 months ago
783
 start
784
 : The function which is the start/entry-point of the `Generator`.
9 months ago
785
9 months ago
786
 param
787
 : The value to pass to `start`.
788
789
 `new` a `Generator` - malloc, and initialise it. When you no longer need the `Generator` use `Generator_dtor` to finalise it.
790
9 months ago
791
 #!C
9 months ago
792
 Generator *gen = Generator_New(mystart, &params);
793
794
 // Generator is used
795
796
 // ... later:
797
 Generator_Delete(gen);
798
9 months ago
799
 ##### void Generator_dtor(Generator *gen)
9 months ago
800
9 months ago
801
 gen
802
 : The `Generator` to destruct.
803
9 months ago
804
 Finalise a `Generator`. Once a `Generator` is no longer needed, it must be finalised:
805
9 months ago
806
 #!C
9 months ago
807
 // earlier...
808
 Generator gen;
6 months ago
809
 Generator_ctor(&gen, generator_stack_size, mystart, &params);
9 months ago
810
811
 // Generator is used
812
813
 // the Generator is no longer needed
814
 Generator_dtor(&gen);
815
816
9 months ago
817
 ##### void Generator_Delete(Generator *gen)
9 months ago
818
9 months ago
819
 gen
820
 : The `Generator` to delete.
821
9 months ago
822
 Finalise then `free()` a `Generator`. Once a `new`ed `Generator` is no longer needed, it must be deleted:
823
9 months ago
824
 #!C
9 months ago
825
 // earlier...
826
 Generator *gen = Generator_New(mystart, &params);
827
828
 // Generator is used
829
830
 // the Generator is no longer needed
831
 Generator_Delete(gen);
832
833
9 months ago
834
 ##### bool Generator_Next(Generator *gen, void **value)
9 months ago
835
9 months ago
836
 (returns)
837
 : Whether there is a next value. `true` - there is a next value; `false` - the `Generator` has finished
838
839
 gen
840
 : The `Generator` to get the next value from.
841
842
 value
843
 : Where to store the next value.
844
9 months ago
845
 Get the next value yielded by the `Generator`.
846
9 months ago
847
 #!C
9 months ago
848
 void *value;
849
 while(Generator_Next(gen, &value)){
850
 // use value here
9 months ago
17
851
 }
9 months ago
852
9 months ago
853
 The `Generator` feeds values to its client using `Generator_Yield()` - it is these values which `Generator_Next()` sets, in the example, `value` to.
9 months ago
854
9 months ago
855
 When a `Generator` is finished it returns from `start`. When you call `Generator_Yield()` on a finished `Generator` it returns `false` and `value` will be the return value from `start`.
856
9 months ago
857
 ##### bool Generator_Yield(void *value)
9 months ago
858
9 months ago
859
 (returns)
860
 : Whether the `Generator` should do more.
9 months ago
861
9 months ago
862
 value
863
 : The `Generator`'s next value.
864
865
 Yield a value from a `Generator`.
866
9 months ago
867
 #!C
9 months ago
868
 bool domore = Generator_Yield(value);
869
9 months ago
870
 `value` is then provided by `Generator_Next()` as the next value from the generator.
9 months ago
871
9 months ago
872
 The `bool` returned by `Generator_Yield()` says whether more values should be provided by your generator function. `true` - provide more values if there are any. `false` - close files, free memory, free up any other resources and `return`. `false` is returned when the `Generator` is being finalised before it has finished, ie the client has exited its `for`-loop early.
873
9 months ago
874
 ## Coroutine
875
4 months ago
876
 ##### Coroutine_Err
9 months ago
877
4 months ago
878
 The enum of errors:
9 months ago
879
4 months ago
880
 Coroutine_OK
881
 : Everything is OK. This is 0
9 months ago
882
4 months ago
883
 Coroutine_Err_SystemNotRunning
884
 : A `Coroutine` must be running to do this
9 months ago
885
4 months ago
886
 Coroutine_Err_SystemRunning
887
 : The `Coroutine` system must not be running to do this
9 months ago
888
4 months ago
889
 Coroutine_Err_NoStack
890
 : Not enough stack is available
891
892
 Coroutine_Err_CoroutineFromWrongThread
893
 : Trying to do something on one thread to a `Coroutine` from a different thread
894
895
 Coroutine_Err_ACoroutineIsAlreadyRunning
896
 : Trying `Coroutine_RunCoroutine` a `Coroutine`
897
898
 Coroutine_Err_ExitWithRunningCoroutines
899
 : All `Coroutine`s must be complete
900
901
 Coroutine_Err_StackOverrun
902
 : Stack overrun detected
903
904
 Coroutine_Err_InternalInsistency
905
 : Something didn't match inside the system
906
907
 Coroutine_Err_CouldNotInitialiseSystem
908
 : Something went wrong initialising (eg couldn't create a lock)
909
910
 Coroutine_Err_WrongState
911
 : It's in the wrong statem, eg trying to `Coroutine_Continue` a completed `Coroutine`
912
913
 Coroutine_Err_Canceled
914
 : It's canceled
915
7 months ago
916
 ##### Coroutine_SetStackLimit(void *limit)
917
6 months ago
918
 limit
919
 : The location (low address) of the stack's end.
920
7 months ago
921
 Set the limit of the stack. This is used to determine more accurately whether `Coroutine_CanStartCoroutine()`
922
4 months ago
923
 ##### Coroutine_Report Coroutine_GetReport()
9 months ago
924
6 months ago
925
 (returns)
926
 : A report from this run of the Coroutine system.
927
9 months ago
928
 #!C
9 months ago
929
 typedef struct Coroutine_Report {
930
 unsigned coroutines_created;
931
 unsigned coroutines_pool_size;
932
 unsigned lowest_headroom;
933
 } Coroutine_Report;
934
935
 coroutines_created
936
 : How many coroutines were created
937
938
 coroutines_pool_size
939
 : The size of the coroutine pool (count of available, free `Coroutine` objects) when the system stopped. This is also the peak number of active coroutines. This will give you an idea of how much stack was needed for your coroutines.
940
941
 lowest_headroom
4 months ago
942
 : The lowest headroom (unused
9 months ago
943
4 months ago
944
 largest_stack
945
 : The largest stack requested for any `Coroutine`.
946
4 months ago
947
 ##### Coroutine_CheckIntegrity()
4 months ago
948
4 months ago
949
 (returns)
950
 : `Coroutine_Err` for any problem
4 months ago
951
4 months ago
952
 Check the integrity of the coroutine system, and `printf()` any problems.
953
9 months ago
954
 ##### Coroutine_Start
9 months ago
955
9 months ago
956
 #!C
9 months ago
957
 void *(*)(void *param)
958
9 months ago
959
 The entry function for a coroutine. The `param` is the value passed to `Coroutine_Continue`, and the `void *` return value can be accessed through the `Coroutine` object using `Coroutine_GetValue()`.
9 months ago
960
4 months ago
961
 ##### Coroutine_SystemStart
962
963
 #!C
964
 Coroutine_Err (*)(void *)
965
966
 The entry function for `Coroutine_RunSystem`.
967
968
 ##### Coroutine_Err Coroutine_RunSystem(Coroutine_SystemStart start, void *value)
969
970
 (returns)
971
 : `Coroutine_OK` or an error. If the system starts, this will be the value returned by `start`.
972
973
 start
974
 : The function to call with the `Coroutine` system started. It is expected that this routine will
975
 start a `Coroutine`.
976
977
 value
978
 : The value to pass to `start`.
979
6 months ago
980
 ##### Coroutine *Coroutine_New(size_t size, Coroutine_Start start)
9 months ago
981
6 months ago
982
 (returns)
983
 A new Coroutine, or `NULL` if there was a failure, such as insufficient stack for the new Coroutine.
984
985
 size
986
 : The stack size given to this Coroutine.
987
988
 start
989
 : The routine called to start the Coroutine.
990
6 months ago
991
 Create a new `Coroutine`. The `Coroutine` system must be started to create a `Coroutine`. The stack size available to the coroutine will be `COROUTINE_STACK_SIZE` defined in `coroutine.h`. When you have finished with your `Coroutine`, use `Coroutine_Delete()` to delete it. If there is not enough space for a new `Coroutine` on your stack, `NULL` will be returned.
9 months ago
992
4 months ago
993
 ##### Coroutine_Err Coroutine_Run_Coroutine(Coroutine *cor, void *value)
9 months ago
994
4 months ago
995
 (returns)
996
 : any problem, or `Coroutine_OK`
997
6 months ago
998
 cor
999
 : The Coroutine to run.
1000
1001
 value
1002
 : The value to pass to the Coroutine's `start` routine.
1003
7 months ago
1004
 Run the `Coroutine` and return when it returns. This is how to start coroutines running in the coroutine system. It is an error for the run coroutine to return before all other coroutines have completed, and the coroutine system must be started to call this.
9 months ago
1005
4 months ago
1006
 ##### Coroutine_Err Coroutine_Run(size_t size, Coroutine_Start start, void *value, void **result)
9 months ago
1007
6 months ago
1008
 (returns)
4 months ago
1009
 : `Coroutine_OK` or any problem
6 months ago
1010
1011
 size
1012
 : The stack size to give to the Corotuine.
1013
1014
 start
1015
 : The routine to start the Coroutine.
1016
1017
 value
1018
 : The value to pass to `start()`.
1019
1020
 result
1021
 : Where to store the return value from `start(value)`. This may be `NULL`.
1022
6 months ago
1023
 `start(value)` is called from within a coroutine and its value returned in `*result`.
1024
 If this completes without any failure, `false` is returned, otherwise, typically
1025
 because `Coroutine_New()` returned `NULL`, `true` is returned. `result` may be `NULL` if you don't
1026
 need the resturn value from `start()`.
1027
 When the coroutine system is active - you are already running in a coroutine - `start(value)`
1028
 is simply called and its result returned in `*result`. When the Coroutine system is not running,
1029
 `Coroutine_Run()` starts it, creates a `Coroutine` and runs that Coroutine to call `start(calue)`
6 months ago
1030
 and return value is returned in `*result`, then stops the Coroutine system. If you need to force
1031
 a new Coroutine to be created, with a particular stack size to call `start(value)`, then use
1032
 `Coroutine_Chain()` instead.
9 months ago
1033
4 months ago
1034
 The total stack allowed for all coroutines running on any thread is the size of the call stack on that thread.
1035
9 months ago
1036
 ##### void Coroutine_Delete(Coroutine *cor)
9 months ago
1037
6 months ago
1038
 cor
1039
 : The Coroutine to delete.
1040
9 months ago
1041
 Use `Coroutine_Delete()` to delete a coroutine when it is no longer needed. It is an error to attempt to delete a coroutine which is running.
9 months ago
1042
4 months ago
1043
 ##### Coroutine_Err Coroutine_Continue(Coroutine *cor, void *value, bool early)
9 months ago
1044
4 months ago
1045
 (returns)
4 months ago
1046
 : `Coroutine_OK` or any error.
4 months ago
1047
6 months ago
1048
 cor
1049
 : The Coroutine to continue.
1050
1051
 value
1052
 : The value to return from `cor`'s yield function.
1053
1054
 early
1055
 : Whether to continue `cor` early (`true`), or late (`false`). Early means before other Coroutines which are waiting
1056
 to be called, whereas late means after them.
1057
4 months ago
1058
 Continue the given `Coroutine`. `value` is passed to the coroutine, as `param` to the `start` function, or as the return value from `Coroutine_Yield`. `early` determines whether the continued coroutine will be run next, or after all the other, currently runnable, coroutines. If the `Coroutine` is already runnable, nothing is done, and `false` is returned. If the `Coroutine` is free, or complete, nothing is done and `true` is returned to show there was a problem.
9 months ago
1059
9 months ago
1060
 ##### void *Coroutine_Yield(void *value, Coroutine_YieldCallback on_yield, void *this)
9 months ago
1061
6 months ago
1062
 value
1063
 : The value to yield fropm the coroutine.
1064
1065
 on_yield
1066
 : A callback to be called once this Coroutine has yielded, but before another one has been continued.
1067
1068
 this
1069
 : The parameter to pass to `on_yield`.
1070
9 months ago
1071
 Yield `value` from the current coroutine; this coroutine is moved to the list of coroutines waiting to be continued. The next runable coroutine is run - either by its start routine being called with `value` as its `param`, or by `value`being returned from its `Coroutine_Yield()`.
1072
9 months ago
1073
 ##### void *Coroutine_GetValue(Coroutine *cor)
9 months ago
1074
6 months ago
1075
 (returns)
1076
 : The Coroutine's value - the last yielded or returned value.
1077
1078
 cor
1079
 : The Coroutine to query.
1080
9 months ago
1081
 Return the `Coroutine`'s value - the value last yielded, or returned by its `start` routine.
1082
9 months ago
1083
 ##### Coroutine *Coroutine_GetActive()
9 months ago
1084
6 months ago
1085
 (returns)
1086
 : The currently active Coroutine.
1087
9 months ago
1088
 Return whihc coroutine is currently running, ie the caller's `Coroutine`.
1089
9 months ago
1090
 ##### bool Coroutine_IsRunning(Coroutine *cor)
9 months ago
1091
6 months ago
1092
 (returns)
1093
 : Whether `cor` is running - it's the active coroutine or waiting to be continued.
1094
1095
 cor
1096
 : The Coroutine to query.
1097
9 months ago
1098
 Return whether the given coroutine is still running - it may be running, ready to run, or waiting to be continued, but won't have returned from its `start` function.
9 months ago
1099
7 months ago
1100
 ##### bool Coroutine_IsComplete(Coroutine *cor)
1101
6 months ago
1102
 (returns)
1103
 : Whether `cor` is complete, ie has returned from `start()`./
1104
1105
 cor
1106
 : The Coroutine to query.
1107
7 months ago
1108
 Return whether the given coroutine is complete - is has returned from its `start` function.
1109
8 months ago
1110
 ##### intptr_t Coroutine_GetStackHeadroom()
9 months ago
1111
6 months ago
1112
 (returns)
1113
 : The amount of stack headroom.
1114
9 months ago
1115
 Return the headroom available in the current coroutine's stack. This can be used to detect when your coroutine is nearing its stack limit, and then use `Coroutine_Chain()` to continue in a new chunk of coroutine stack.
9 months ago
1116
6 months ago
1117
 ##### bool Coroutine_CanStartCoroutine(size_t size)
9 months ago
1118
6 months ago
1119
 (returns)
1120
 : Whether a Coroutine with the given amount of stack could be created.
1121
1122
 size
1123
 : The amount of stack in the Coroutine we might want to create.
1124
7 months ago
1125
 Return whether the coroutine system can start a new coroutine. This check can only be done with the coroutine system active (currently running
7 months ago
1126
 a coroutine). If there's a free coroutine, or enough space on the stack for a new one, then this will return `true`. To set the limit of the
1127
 stack use `Coroutine_SetStackLimit()`
9 months ago
1128
7 months ago
1129
 ##### void *Coroutine_GetStackHWM(void)
1130
6 months ago
1131
 (returns)
1132
 : The lowest address where the active Coroutine's stack has grown to ever.
1133
7 months ago
1134
 Find out where this coroutine's guard patterns end. This is intended as a part of the tools to measure how much stack something is using:
1135
1136
 #!C
1137
 Coroutine_ClearStackForHWM();
1138
 char *before = (char *)Coroutine_GetStackHWM();
1139
 // do the thing you want to measure here
1140
 char *after = (char *)Coroutine_GetStackHWM();
1141
 intptr_t amount_used = before - after;
1142
1143
 ##### void Coroutine_ClearStackForHWM(void)
1144
1145
 Fill the unused stack in this coroutine with a guard pattern. This is intended as a part of the tools to measure how much stack something is using:
1146
1147
 #!C
1148
 Coroutine_ClearStackForHWM();
1149
 char *before = (char *)Coroutine_GetStackHWM();
1150
 // do the thing you want to measure here
1151
 char *after = (char *)Coroutine_GetStackHWM();
1152
 intptr_t amount_used = before - after;
1153
9 months ago
1154
 ##### void *Coroutine_GetCStackTop()
9 months ago
1155
6 months ago
1156
 (returns)
1157
 : Where the Coroutine system has reached in the C stack.
1158
9 months ago
1159
 Return an address which is near to the top of used C stack.
1160
4 months ago
1161
 ##### Coroutine_Err Coroutine_Chain(size_t size, Coroutine_Start start, void *value, void **result)
9 months ago
1162
6 months ago
1163
 (returns)
4 months ago
1164
 : Whether there was a problem. `Coroutine_OK` - `start(value)` was run; an error - there was a problem.
6 months ago
1165
1166
 size
1167
 : The amount of stack to give the chained Coroutine.
1168
1169
 start
1170
 : The entry point ot the chained Coroutine.
1171
1172
 value
1173
 : The value to pass to `start()`
1174
1175
 result
1176
 : Where to store the return value from `start(value)`. This may be `NULL`.
1177
6 months ago
1178
 Run `start` with `value` on a new coroutine, and return its return value in `*result`. `result`
1179
 may be NULL. `Coroutine_Run()` returns `false` if nothing fails, and `true` if something went wrong,
6 months ago
1180
 usually when `Coroutine_New()` ran out of stack. `stack_size` is the amount of stack made available
1181
 to the chained Coroutine.
6 months ago
1182
 It is expected that `Coroutine_Chain()` will be used when your coroutine is running short
1183
 of stack - it is not an alternative to `Coroutine_Run()`.
6 months ago
1184
Last month
1185
 ##### void Coroutine_Dump_()
6 months ago
1186
1187
 *Do not use this function in production code*
1188
1189
 This prints the current state of the Coroutine system. It is used for development, and is not part of the official interface.
1190