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Diffstat (limited to 'nuttx/sched/pthread_once.c')
-rw-r--r-- | nuttx/sched/pthread_once.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/nuttx/sched/pthread_once.c b/nuttx/sched/pthread_once.c new file mode 100644 index 000000000..413300472 --- /dev/null +++ b/nuttx/sched/pthread_once.c @@ -0,0 +1,128 @@ +/******************************************************************************** + * sched/pthread_once.c + * + * Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ********************************************************************************/ + +/******************************************************************************** + * Included Files + ********************************************************************************/ + +#include <nuttx/config.h> + +#include <stdbool.h> +#include <pthread.h> +#include <sched.h> +#include <errno.h> +#include <debug.h> + +/******************************************************************************** + * Pre-processor Definitions + ********************************************************************************/ + +/******************************************************************************** + * Private Type Declarations + ********************************************************************************/ + +/******************************************************************************** + * Global Variables + ********************************************************************************/ + +/******************************************************************************** + * Private Variables + ********************************************************************************/ + +/******************************************************************************** + * Private Function Prototypes + ********************************************************************************/ + +/******************************************************************************** + * Public Functions + ********************************************************************************/ + +/******************************************************************************** + * Name: pthread_once + * + * Description: + * The first call to pthread_once() by any thread with a given once_control, + * will call the init_routine with no arguments. Subsequent calls to + * pthread_once() with the same once_control will have no effect. On return + * from pthread_once(), init_routine will have completed. + * + * Parameters: + * once_control - Determines if init_routine should be called. once_control + * should be declared and intialized as follows: + * + * pthread_once_t once_control = PTHREAD_ONCE_INIT; + * + * PTHREAD_ONCE_INIT is defined in pthread.h + * init_routine - The initialization routine that will be called once. + * + * Return Value: + * 0 (OK) on success or EINVAL if either once_control or init_routine are + * invalid + * + * Assumptions: + * + ********************************************************************************/ + +int pthread_once(FAR pthread_once_t *once_control, + CODE void (*init_routine)(void)) +{ + /* Sanity checks */ + + if (once_control && init_routine) + { + /* Prohibit pre-emption while we test and set the once_control */ + + sched_lock(); + 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(); + return OK; + } + + /* One of the two arguments is NULL */ + + return EINVAL; +} |