thread: Fix confusion between NULL and 0.

[gnulib.git] / lib / glthread / thread.h

diff --git a/lib/glthread/thread.h b/lib/glthread/thread.h
index bd8575f..a0d40f8 100644 (file)
--- a/lib/glthread/thread.h
+++ b/lib/glthread/thread.h
@@ -1,5 +1,5 @@
 /* Creating and controlling threads.
-   Copyright (C) 2005-2008 Free Software Foundation, Inc.
+   Copyright (C) 2005-2011 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -137,6 +137,9 @@ extern int glthread_in_use (void);
 
 /* -------------------------- gl_thread_t datatype -------------------------- */
 
+/* This choice of gl_thread_t assumes that
+     pthread_equal (a, b)  is equivalent to  ((a) == (b)).
+   This is the case on all platforms in use in 2008.  */
 typedef pthread_t gl_thread_t;
 # define glthread_create(THREADP, FUNC, ARG) \
     (pthread_in_use () ? pthread_create (THREADP, NULL, FUNC, ARG) : ENOSYS)
@@ -156,6 +159,10 @@ typedef pthread_t gl_thread_t;
 #  define glthread_atfork(PREPARE_FUNC, PARENT_FUNC, CHILD_FUNC) 0
 # endif
 
+# ifdef __cplusplus
+}
+# endif
+
 #endif
 
 /* ========================================================================= */
@@ -198,11 +205,15 @@ typedef pth_t gl_thread_t;
 # define glthread_join(THREAD, RETVALP) \
     (pth_in_use () && !pth_join (THREAD, RETVALP) ? errno : 0)
 # define gl_thread_self() \
-    (pth_in_use () ? (void *) pth_self () : 0)
+    (pth_in_use () ? (void *) pth_self () : NULL)
 # define gl_thread_exit(RETVAL) \
     (pth_in_use () ? pth_exit (RETVAL) : 0)
 # define glthread_atfork(PREPARE_FUNC, PARENT_FUNC, CHILD_FUNC) 0
 
+# ifdef __cplusplus
+}
+# endif
+
 #endif
 
 /* ========================================================================= */
@@ -242,16 +253,64 @@ typedef thread_t gl_thread_t;
 # define glthread_create(THREADP, FUNC, ARG) \
     (thread_in_use () ? thr_create (NULL, 0, FUNC, ARG, 0, THREADP) : 0)
 # define glthread_sigmask(HOW, SET, OSET) \
-    (pthread_in_use () ? sigprocmask (HOW, SET, OSET) : 0)
+    (thread_in_use () ? sigprocmask (HOW, SET, OSET) : 0)
 # define glthread_join(THREAD, RETVALP) \
-    (pthread_in_use () ? thr_join (THREAD, NULL, RETVALP) : 0)
+    (thread_in_use () ? thr_join (THREAD, NULL, RETVALP) : 0)
 # define gl_thread_self() \
-    (pthread_in_use () ? (void *) thr_self () : 0)
+    (thread_in_use () ? (void *) thr_self () : NULL)
 # define gl_thread_exit(RETVAL) \
-    (pthread_in_use () ? thr_exit (RETVAL) : 0)
+    (thread_in_use () ? thr_exit (RETVAL) : 0)
 # define glthread_atfork(PREPARE_FUNC, PARENT_FUNC, CHILD_FUNC) 0
+
+# ifdef __cplusplus
+}
+# endif
+
 #endif
 
+/* ========================================================================= */
+
+#if USE_WIN32_THREADS
+
+# include <windows.h>
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+/* -------------------------- gl_thread_t datatype -------------------------- */
+
+/* The gl_thread_t is a pointer to a structure in memory.
+   Why not the thread handle?  If it were the thread handle, it would be hard
+   to implement gl_thread_self() (since GetCurrentThread () returns a pseudo-
+   handle, DuplicateHandle (GetCurrentThread ()) returns a handle that must be
+   closed afterwards, and there is no function for quickly retrieving a thread
+   handle from its id).
+   Why not the thread id?  I tried it.  It did not work: Sometimes ids appeared
+   that did not belong to running threads, and glthread_join failed with ESRCH.
+ */
+typedef struct gl_thread_struct *gl_thread_t;
+# define glthread_create(THREADP, FUNC, ARG) \
+    glthread_create_func (THREADP, FUNC, ARG)
+# define glthread_sigmask(HOW, SET, OSET) \
+    /* unsupported */ 0
+# define glthread_join(THREAD, RETVALP) \
+    glthread_join_func (THREAD, RETVALP)
+# define gl_thread_self() \
+    gl_thread_self_func ()
+# define gl_thread_exit(RETVAL) \
+    gl_thread_exit_func (RETVAL)
+# define glthread_atfork(PREPARE_FUNC, PARENT_FUNC, CHILD_FUNC) 0
+extern int glthread_create_func (gl_thread_t *threadp, void * (*func) (void *), void *arg);
+extern int glthread_join_func (gl_thread_t thread, void **retvalp);
+extern gl_thread_t gl_thread_self_func (void);
+extern int gl_thread_exit_func (void *retval);
+
+# ifdef __cplusplus
+}
+# endif
+
+#endif
 
 /* ========================================================================= */
 
@@ -263,17 +322,20 @@ typedef int gl_thread_t;
 # define glthread_create(THREADP, FUNC, ARG) ENOSYS
 # define glthread_sigmask(HOW, SET, OSET) 0
 # define glthread_join(THREAD, RETVALP) 0
-# define gl_thread_self() NULL
+# define gl_thread_self() 0
 # define gl_thread_exit(RETVAL) 0
 # define glthread_atfork(PREPARE_FUNC, PARENT_FUNC, CHILD_FUNC) 0
 
 #endif
 
-
 /* ========================================================================= */
 
 /* Macros with built-in error handling.  */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 static inline gl_thread_t
 gl_thread_create (void *(*func) (void *arg), void *arg)
 {
@@ -307,4 +369,8 @@ gl_thread_create (void *(*func) (void *arg), void *arg)
      }                                               \
    while (0)
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* _GLTHREAD_THREAD_H */