From 82ba818ff456bcd6d56a06226e3f27e98fbb55c3 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Thu, 14 Aug 2025 22:58:58 -0500 Subject: removing all downloaded devdocs files --- devdocs/c/thread%2Fcall_once.html | 55 --------------------------------------- 1 file changed, 55 deletions(-) delete mode 100644 devdocs/c/thread%2Fcall_once.html (limited to 'devdocs/c/thread%2Fcall_once.html') diff --git a/devdocs/c/thread%2Fcall_once.html b/devdocs/c/thread%2Fcall_once.html deleted file mode 100644 index c49a1c35..00000000 --- a/devdocs/c/thread%2Fcall_once.html +++ /dev/null @@ -1,55 +0,0 @@ -

call_once, once_flag, ONCE_FLAG_INIT

Defined in header <threads.h> 
void call_once( once_flag* flag, void (*func)(void) );
-		 (1) (since C11) 
typedef /* unspecified */ once_flag
-		 (2) (since C11) 
#define ONCE_FLAG_INIT /* unspecified */
-		 (3) (since C11)
-1) Calls function func exactly once, even if invoked from several threads. The completion of the function func synchronizes with all previous or subsequent calls to call_once with the same flag variable.
-2) Complete object type capable of holding a flag used by call_once.
-3) Expands to a value that can be used to initialize an object of type once_flag.

Parameters

- - -
flag - pointer to an object of type call_once that is used to ensure func is called only once
func - the function to execute only once

Return value

(none)

-

Notes

The POSIX equivalent of this function is pthread_once.

-

Example

#include <stdio.h>
-#include <threads.h>
- 
-void do_once(void) {
-    puts("called once");
-}
- 
-static once_flag flag = ONCE_FLAG_INIT;
-int func(void* data)
-{
-    call_once(&flag, do_once);
-}
- 
-int main(void)
-{
-    thrd_t t1, t2, t3, t4;
-    thrd_create(&t1, func, NULL);
-    thrd_create(&t2, func, NULL);
-    thrd_create(&t3, func, NULL);
-    thrd_create(&t4, func, NULL);
- 
-    thrd_join(t1, NULL);
-    thrd_join(t2, NULL);
-    thrd_join(t3, NULL);
-    thrd_join(t4, NULL);
-}

Output:

-
called once

References

See also

-
C++ documentation for call_once
-

- © cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
- https://en.cppreference.com/w/c/thread/call_once -

-
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