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libs/libc: Update pthread_once according to the specification

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OpenGroup specification was updated regarding the return value for
pthread_once, which after Issue 7 states that "the [EINVAL] error for an
uninitialized pthread_once_t object is removed; this condition results
in undefined behavior".
This commit is contained in:
Gustavo Henrique Nihei 2021-03-30 14:04:27 -03:00 committed by Xiang Xiao
parent bea6e0ddd7
commit 0109bcad8c
1 changed files with 21 additions and 24 deletions
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45
libs/libc/pthread/pthread_once.c
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@ -24,10 +24,10 @@
#include <nuttx/config.h> #include <nuttx/config.h>
#include <assert.h>
#include <stdbool.h> #include <stdbool.h>
#include <pthread.h> #include <pthread.h>
#include <sched.h> #include <sched.h>
#include <errno.h>
#include <debug.h> #include <debug.h>
/**************************************************************************** /****************************************************************************
@ -38,14 +38,14 @@
* Name: pthread_once * Name: pthread_once
* *
* Description: * Description:
* The first call to pthread_once() by any thread with a given * The first call to pthread_once() by any thread with a given
* once_control, will call the init_routine with no arguments. Subsequent * once_control, will call the init_routine with no arguments. Subsequent
* calls to pthread_once() with the same once_control will have no effect. * calls to pthread_once() with the same once_control will have no effect.
* On return from pthread_once(), init_routine will have completed. * On return from pthread_once(), init_routine will have completed.
* *
* Input Parameters: * Input Parameters:
* once_control - Determines if init_routine should be called. * once_control - Determines if init_routine should be called.
* once_control should be declared and initializeed as follows: * once_control should be declared and initialized as follows:
* *
* pthread_once_t once_control = PTHREAD_ONCE_INIT; * pthread_once_t once_control = PTHREAD_ONCE_INIT;
* *
@ -53,8 +53,8 @@
* init_routine - The initialization routine that will be called once. * init_routine - The initialization routine that will be called once.
* *
* Returned Value: * Returned Value:
* 0 (OK) on success or EINVAL if either once_control or init_routine are * 0 (OK) on success or an error number shall be returned to
* invalid * indicate the error.
* *
* Assumptions: * Assumptions:
* *
@ -65,31 +65,28 @@ int pthread_once(FAR pthread_once_t *once_control,
{ {
/* Sanity checks */ /* Sanity checks */
if (once_control && init_routine) DEBUGASSERT(once_control != NULL);
DEBUGASSERT(init_routine != NULL);
/* Prohibit pre-emption while we test and set the once_control. */
sched_lock();
if (!*once_control)
{ {
/* Prohibit pre-emption while we test and set the once_control */ *once_control = true;
sched_lock(); /* Call the init_routine with pre-emption enabled. */
if (!*once_control)
{
*once_control = true;
/* Call the init_routine with pre-emption enabled. */
sched_unlock();
init_routine();
return OK;
}
/* The init_routine has already been called.
* Restore pre-emption and return
*/
sched_unlock(); sched_unlock();
init_routine();
return OK; return OK;
} }
/* One of the two arguments is NULL */ /* The init_routine has already been called.
* Restore pre-emption and return.
*/
return EINVAL; sched_unlock();
return OK;
} }