[ViewVC] Diff of: cvs/libcoro/coro.h

Comparing libcoro/coro.h (file contents):
Revision 1.51 by root, Wed Dec 5 01:09:12 2012 UTC vs.
Revision 1.52 by root, Fri Dec 7 14:21:09 2012 UTC

  * 2011-06-08 maybe properly implement weird windows amd64 calling conventions.
  * 2011-07-03 rely on __GCC_HAVE_DWARF2_CFI_ASM for cfi detection.
  * 2011-08-08 cygwin trashes stacks, use pthreads with double stack on cygwin.
  * 2012-12-04 reduce misprediction penalty for x86/amd64 assembly switcher.
  * 2012-12-05 experimental fiber backend (allocates stack twice).
+ * 2012-12-07 API version 3 - add coro_stack_alloc/coro_stack_free.
  */
 #ifndef CORO_H
 #define CORO_H
 #if __cplusplus
 extern "C" {
 #endif
-#define CORO_VERSION 2
-/*
- * Changes since API version 1:
- * replaced bogus -DCORO_LOOSE with gramatically more correct -DCORO_LOSER
- */
 /*
  * This library consists of only three files
  * coro.h, coro.c and LICENSE (and optionally README)
  *
  * It implements what is known as coroutines, in a hopefully
- * portable way. At the moment you have to define which kind
+ * portable way.
- * of implementation flavour you want:
+ *
+ * All compiletime symbols must be defined both when including coro.h
+ * (using libcoro) as well as when compiling coro.c (the implementation).
+ *
+ * You can manually specify which flavour you want. If you don't define
+ * any of these, libcoro tries to choose a safe and fast default:
  *
  * -DCORO_UCONTEXT
  *
  *    This flavour uses SUSv2's get/set/swap/makecontext functions that
- *    unfortunately only newer unices support.
+ *    unfortunately only some unices support, and is quite slow.
  *
  * -DCORO_SJLJ
  *
  *    This flavour uses SUSv2's setjmp/longjmp and sigaltstack functions to
  *    do it's job. Coroutine creation is much slower than UCONTEXT, but
- *    context switching is often a bit cheaper. It should work on almost
+ *    context switching is a bit cheaper. It should work on almost all unices.
- *    all unices.
  *
  * -DCORO_LINUX
  *
+ *    CORO_SJLJ variant.
  *    Old GNU/Linux systems (<= glibc-2.1) only work with this implementation
  *    (it is very fast and therefore recommended over other methods, but
  *    doesn't work with anything newer).
  *
  * -DCORO_LOSER
  *
+ *    CORO_SJLJ variant.
  *    Microsoft's highly proprietary platform doesn't support sigaltstack, and
- *    this automatically selects a suitable workaround for this platform.
+ *    this selects a suitable workaround for this platform. It might not work
- *    (untested)
+ *    with your compiler though - it has only been tested with MSVC 6.
  *
  * -DCORO_FIBER
  *
- *    slower, but probably more portable variant for the Microsoft operating
+ *    Slower, but probably more portable variant for the Microsoft operating
- *    system, using fibers. ignores your stack.
+ *    system, using fibers. Ignores the passed stack and allocates it internally.
+ *    Also, due to bugs in cygwin, this does not work with cygwin.
  *
  * -DCORO_IRIX
  *
+ *    CORO_SJLJ variant.
- *    SGI's version of Microsoft's NT ;)
+ *    For SGI's version of Microsoft's NT ;)
  *
  * -DCORO_ASM
  *
- *    Handcoded assembly, known to work only on a few architectures/ABI:
+ *    Hand coded assembly, known to work only on a few architectures/ABI:
- *    GCC + x86/IA32 and amd64/x86_64 + GNU/Linux and a few BSDs.
+ *    GCC + x86/IA32 and amd64/x86_64 + GNU/Linux and a few BSDs. Fastest choice,
+ *    if it works.
  *
  * -DCORO_PTHREAD
  *
  *    Use the pthread API. You have to provide <pthread.h> and -lpthread.
  *    This is likely the slowest backend, and it also does not support fork(),
  *    so avoid it at all costs.
  *
  * If you define neither of these symbols, coro.h will try to autodetect
- * the model. This currently works for CORO_LOSER only. For the other
+ * the best/safest model. To help with the autodetection, you should check
- * alternatives you should check (e.g. using autoconf) and define the
+ * (e.g. using autoconf) and define the following symbols: HAVE_UCONTEXT_H
- * following symbols: HAVE_UCONTEXT_H / HAVE_SETJMP_H / HAVE_SIGALTSTACK.
+ * / HAVE_SETJMP_H / HAVE_SIGALTSTACK.
+ */
+/*
+ * Changes when the API changes incompatibly.
+ * This is ONLY the API version - there is no ABI compatibility between releases.
- */
+ *
+ * Changes in API version 2:
+ * replaced bogus -DCORO_LOOSE with grammatically more correct -DCORO_LOSER
+ * Changes in API version 3:
+ * introduced stack management (CORO_STACKALLOC)
+ */
+#define CORO_VERSION 3
+#include <stddef.h>
 /*
  * This is the type for the initialization function of a new coroutine.
  */
 typedef void (*coro_func)(void *);
  * uninitialised coro_context, it expects a pointer to the entry function
  * and the single pointer value that is given to it as argument.
  *
  * Allocating/deallocating the stack is your own responsibility.
  *
- * As a special case, if coro, arg, sptr and ssize are all zero,
+ * As a special case, if coro, arg, sptr and ssze are all zero,
  * then an "empty" coro_context will be created that is suitable
  * as an initial source for coro_transfer.
  *
  * This function is not reentrant, but putting a mutex around it
  * will work.
  */
 void coro_create (coro_context *ctx, /* an uninitialised coro_context */
                   coro_func coro,    /* the coroutine code to be executed */
                   void *arg,         /* a single pointer passed to the coro */
                   void *sptr,        /* start of stack area */
-                  long ssize);       /* size of stack area */
+                  size_t ssze);      /* size of stack area in bytes */
 /*
  * The following prototype defines the coroutine switching function. It is
- * usually implemented as a macro, so watch out.
+ * sometimes implemented as a macro, so watch out.
  *
  * This function is thread-safe and reentrant.
  */
 #if 0
 void coro_transfer (coro_context *prev, coro_context *next);
 #endif
 /*
- * The following prototype defines the coroutine destroy function. It is
+ * The following prototype defines the coroutine destroy function. It
- * usually implemented as a macro, so watch out. It also serves
+ * is sometimes implemented as a macro, so watch out. It also serves no
- * no purpose unless you want to use the CORO_PTHREAD backend,
+ * purpose unless you want to use the CORO_PTHREAD backend, where it is
- * where it is used to clean up the thread. You are responsible
+ * used to clean up the thread. You are responsible for freeing the stack
- * for freeing the stack and the context itself.
+ * and the context itself.
  *
  * This function is thread-safe and reentrant.
  */
 #if 0
 void coro_destroy (coro_context *ctx);
 #endif
+/*****************************************************************************/
+/* optional stack management                                                 */
+/*****************************************************************************/
 /*
- * That was it. No other user-visible functions are implemented here.
+ * You can disable all of the stack management functions by
+ * defining CORO_STACKALLOC to 0. Otherwise, they are enabled by default.
+ *
+ * If stack management is enabled, you can influence the implementation via these
+ * symbols:
+ *
+ * -DCORO_USE_VALGRIND
+ *
+ *    If defined, then libcoro will include valgrind/valgrind.h and register
+ *    and unregister stacks with valgrind.
+ *
+ * -DCORO_GUARDPAGES=n
+ *
+ *    libcoro will try to use the specified number of guard pages to protect against
+ *    stack overflow. If n is 0, then the feature will be disabled. If it isn't
+ *    defined, then libcoro will choose a suitable default. If guardpages are not
+ *    supported on the platform, then the feature will be silently disabled.
+ */
+#ifndef CORO_STACKALLOC
+# define CORO_STACKALLOC 1
+#endif
+#if CORO_STACKALLOC
+/*
+ * The only allowed operations on these struct members is to read the
+ * "sptr" and "ssze" members to pass it to coro_create, to read the "sptr"
+ * member to see if it is false, in which case the stack isn't allocated,
+ * and to set the "sptr" member to 0, to indicate to coro_stack_free to
+ * not actually do anything.
+ */
+struct coro_stack
+{
+  void *sptr;
+  size_t ssze;
+#if CORO_USE_VALGRIND
+  int valgrind_id;
+#endif
+};
+/*
+ * Try to allocate a stack of at least the given size and return true if
+ * successful, or false otherwise.
+ *
+ * The size is *NOT* specified in bytes, but in units of sizeof (void *),
+ * i.e. the stack is typically 4(8) times larger on 32 bit(64 bit) platforms
+ * then the size passed in.
+ *
+ * If size is 0, then a "suitable" stack size is chosen (usually 1-2MB).
+ */
+int coro_stack_alloc (struct coro_stack *stack, unsigned int size);
+/*
+ * Free the stack allocated by coro_stack_alloc again. It is safe to
+ * call this function on the coro_stack structure even if coro_stack_alloc
+ * failed.
+ */
+void coro_stack_free (struct coro_stack *stack);
+#endif
+/*
+ * That was it. No other user-serviceable parts below here.
  */
 /*****************************************************************************/
 #if !defined CORO_LOSER      && !defined CORO_UCONTEXT \
 #if CORO_UCONTEXT
 # include <ucontext.h>
-struct coro_context {
+struct coro_context
+{
   ucontext_t uc;
 };
 # define coro_transfer(p,n) swapcontext (&((p)->uc), &((n)->uc))
 # define coro_destroy(ctx) (void *)(ctx)
 #elif CORO_SJLJ || CORO_LOSER || CORO_LINUX || CORO_IRIX
 # if defined(CORO_LINUX) && !defined(_GNU_SOURCE)
-#  define _GNU_SOURCE /* for linux libc */
+#  define _GNU_SOURCE /* for glibc */
 # endif
 # if !CORO_LOSER
 #  include <unistd.h>
 # endif
 #  define coro_jmp_buf      sigjmp_buf
 #  define coro_setjmp(env)  sigsetjmp (env, 0)
 #  define coro_longjmp(env) siglongjmp ((env), 1)
 # endif
-struct coro_context {
+struct coro_context
+{
   coro_jmp_buf env;
 };
 # define coro_transfer(p,n) do { if (!coro_setjmp ((p)->env)) coro_longjmp ((n)->env); } while (0)
 # define coro_destroy(ctx) (void *)(ctx)
 #elif CORO_ASM
-struct coro_context {
+struct coro_context
+{
   void **sp; /* must be at offset 0 */
 };
 void __attribute__ ((__noinline__, __regparm__(2)))
 coro_transfer (coro_context *prev, coro_context *next);
 # include <pthread.h>
 extern pthread_mutex_t coro_mutex;
-struct coro_context {
+struct coro_context
+{
   pthread_cond_t cv;
   pthread_t id;
 };
 void coro_transfer (coro_context *prev, coro_context *next);
 void coro_destroy (coro_context *ctx);
 #elif CORO_FIBER
-struct coro_context {
+struct coro_context
+{
   void *fiber;
   /* only used for initialisation */
   coro_func coro;
   void *arg;
 };
+void coro_transfer (coro_context *prev, coro_context *next);
+void coro_destroy (coro_context *ctx);
 #endif
 #if __cplusplus
 }
 #endif

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Comparing libcoro/coro.h (file contents): Revision 1.51 by root, Wed Dec 5 01:09:12 2012 UTC vs. Revision 1.52 by root, Fri Dec 7 14:21:09 2012 UTC

Diff Legend

Comparing libcoro/coro.h (file contents):
Revision 1.51 by root, Wed Dec 5 01:09:12 2012 UTC vs.
Revision 1.52 by root, Fri Dec 7 14:21:09 2012 UTC