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The C and C++ Include Header Files

cat -n /usr/include/python3.14/internal/pycore_condvar.h

     1	#ifndef Py_INTERNAL_CONDVAR_H
     2	#define Py_INTERNAL_CONDVAR_H
     3	
     4	#ifndef Py_BUILD_CORE
     5	#  error "this header requires Py_BUILD_CORE define"
     6	#endif
     7	
     8	#include "pycore_pythread.h"      // _POSIX_THREADS
     9	
    10	
    11	#ifdef _POSIX_THREADS
    12	/*
    13	 * POSIX support
    14	 */
    15	#define Py_HAVE_CONDVAR
    16	
    17	#ifdef HAVE_PTHREAD_H
    18	#  include <pthread.h>            // pthread_mutex_t
    19	#endif
    20	
    21	#define PyMUTEX_T pthread_mutex_t
    22	#define PyCOND_T pthread_cond_t
    23	
    24	#elif defined(NT_THREADS)
    25	/*
    26	 * Windows (XP, 2003 server and later, as well as (hopefully) CE) support
    27	 *
    28	 * Emulated condition variables ones that work with XP and later, plus
    29	 * example native support on VISTA and onwards.
    30	 */
    31	#define Py_HAVE_CONDVAR
    32	
    33	/* include windows if it hasn't been done before */
    34	#ifndef WIN32_LEAN_AND_MEAN
    35	#  define WIN32_LEAN_AND_MEAN
    36	#endif
    37	#include <windows.h>              // CRITICAL_SECTION
    38	
    39	/* options */
    40	/* emulated condition variables are provided for those that want
    41	 * to target Windows XP or earlier. Modify this macro to enable them.
    42	 */
    43	#ifndef _PY_EMULATED_WIN_CV
    44	#define _PY_EMULATED_WIN_CV 0  /* use non-emulated condition variables */
    45	#endif
    46	
    47	/* fall back to emulation if targeting earlier than Vista */
    48	#if !defined NTDDI_VISTA || NTDDI_VERSION < NTDDI_VISTA
    49	#undef _PY_EMULATED_WIN_CV
    50	#define _PY_EMULATED_WIN_CV 1
    51	#endif
    52	
    53	#if _PY_EMULATED_WIN_CV
    54	
    55	typedef CRITICAL_SECTION PyMUTEX_T;
    56	
    57	/* The ConditionVariable object.  From XP onwards it is easily emulated
    58	   with a Semaphore.
    59	   Semaphores are available on Windows XP (2003 server) and later.
    60	   We use a Semaphore rather than an auto-reset event, because although
    61	   an auto-reset event might appear to solve the lost-wakeup bug (race
    62	   condition between releasing the outer lock and waiting) because it
    63	   maintains state even though a wait hasn't happened, there is still
    64	   a lost wakeup problem if more than one thread are interrupted in the
    65	   critical place.  A semaphore solves that, because its state is
    66	   counted, not Boolean.
    67	   Because it is ok to signal a condition variable with no one
    68	   waiting, we need to keep track of the number of
    69	   waiting threads.  Otherwise, the semaphore's state could rise
    70	   without bound.  This also helps reduce the number of "spurious wakeups"
    71	   that would otherwise happen.
    72	 */
    73	
    74	typedef struct _PyCOND_T
    75	{
    76	    HANDLE sem;
    77	    int waiting; /* to allow PyCOND_SIGNAL to be a no-op */
    78	} PyCOND_T;
    79	
    80	#else /* !_PY_EMULATED_WIN_CV */
    81	
    82	/* Use native Windows primitives if build target is Vista or higher */
    83	
    84	/* SRWLOCK is faster and better than CriticalSection */
    85	typedef SRWLOCK PyMUTEX_T;
    86	
    87	typedef CONDITION_VARIABLE  PyCOND_T;
    88	
    89	#endif /* _PY_EMULATED_WIN_CV */
    90	
    91	#endif /* _POSIX_THREADS, NT_THREADS */
    92	
    93	#endif /* Py_INTERNAL_CONDVAR_H */