once.h

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#include <rw/_defs.h>
 
 
#ifdef _RWSTD_REENTRANT
#  ifdef _RWSTD_OS_SUNOS
 
#    include <pthread.h>
#    include <thread.h>
 
#    define _RWSTD_THREAD_ONCE(once, func)   pthread_once (once, func)
#    define _RWSTD_THREAD_YIELD()            thr_yield ()
#    define _RWSTD_ONCE_INIT                 PTHREAD_ONCE_INIT
 
typedef pthread_once_t __rw_once_t;
 
#  elif defined (_RWSTD_POSIX_THREADS)
 
#    include <pthread.h>
 
#    ifndef _RWSTD_NO_PTHREAD_ONCE
 
typedef pthread_once_t __rw_once_t;
 
#      define _RWSTD_THREAD_ONCE(once, func)   pthread_once (once, func)
#      define _RWSTD_ONCE_INIT                 PTHREAD_ONCE_INIT
 
#    else   // if defined (_RWSTD_NO_PTHREAD_ONCE)
 
_RWSTD_NAMESPACE (__rw) {
 
struct __rw_once_t {
    pthread_mutex_t _C_mutex;
    int             _C_init;
};
 
}   // namespace __rw
 
#      define _RWSTD_ONCE_INIT   { PTHREAD_MUTEX_INITIALIZER, -1 }
 
#    endif   // _RWSTD_NO_PTHREAD_ONCE
 
#    ifndef _RWSTD_NO_SCHED_YIELD
#      define _RWSTD_THREAD_YIELD()   sched_yield ()
#    endif   // _RWSTD_NO_SCHED_YIELD
#  elif defined (_RWSTD_DCE_THREADS)
 
#    if defined (_RWSTD_NO_DCE_PTHREAD_H)
#      include <pthread.h>
#    else
#      include <dce/pthread.h>
#    endif
 
_RWSTD_NAMESPACE (__rw) {
 
typedef pthread_once_t __rw_once_t;
 
}   // namespace __rw
 
#    define _RWSTD_THREAD_ONCE(once, func)   pthread_once (once, func)
#    define _RWSTD_THREAD_YIELD()            pthread_yield ()
#    define _RWSTD_ONCE_INIT                 PTHREAD_ONCE_INIT
 
#  elif defined (_WIN32)
 
#    include <windows.h>
 
_RWSTD_NAMESPACE (__rw) {
 
struct __rw_once_t { int _C_init; };
 
}   // namespace __rw
 
#    define _RWSTD_THREAD_YIELD()   Sleep (0)
#    define _RWSTD_ONCE_INIT        { 0 }
#  else   // !_WIN32
 
_RWSTD_NAMESPACE (__rw) {
 
struct __rw_once_t { int _C_init; };
 
}   // namespace __rw
 
#    define _RWSTD_ONCE_INIT   { 0 }
#  endif   // _WIN32
#else   // if !defined (_RWSTD_REENTRANT)
 
_RWSTD_NAMESPACE (__rw) {
 
struct __rw_once_t { int _C_init; };
 
}   // namespace __rw
 
   // defined to a non-zero value to help detect uninitialized
   // __rw_once_t objects
#  define _RWSTD_ONCE_INIT   { -1 }
#endif   // _RWSTD_REENTRANT
 
 
#ifndef _RWSTD_THREAD_YIELD
#  define _RWSTD_THREAD_YIELD()   (void)0
#endif   // _RWSTD_THREAD_YIELD
 
 
_RWSTD_NAMESPACE (__rw) {
 
extern "C" {
 
#if !defined (_RWSTD_MSVC) || !defined (_RWSTD_REENTRANT)
 
_RWSTD_EXPORT int
__rw_once (__rw_once_t*, void (*)());
 
#else   // _RWSTD_MSVC && _RWSTD_REENTRANT
 
// MSVC by default assumes that functions with C linkage don't
// throw exceptions and issues warning "function assumed not
// to throw an exception but does". Specifying an exception
// specification using the throw(...) extension prevents this
// problem.
// Note: functions with C linkage passed as an argument to
// __rw_once() should also be declared with the appropriate
// exception specification if it throws an exception in order
// to avoid resource leaks due to destructors of objects with
// auto storage duration not being run otherwise.
_RWSTD_EXPORT int
__rw_once (__rw_once_t*, void (*)() throw (...)) throw (...);
 
#endif   // !_RWSTD_MSVC || !_RWSTD_REENTRANT
 
}   // extern "C"
 
 
}   // namespace __rw