PTHREAD_CREATE(3)

NAME
pthread_create - create a new thread

SYNOPSIS
#include <pthread.h>
int
pthread_create(pthread_t *restrict thread, const pthread_attr_t *restrict attr, void *(*start_routine)(void *), void *restrict arg);

DESCRIPTION
The pthread_create() function is used to create a new thread, with attributes specified by attr, within a process. If attr is NULL, the default attributes are used. If the attributes specified by attr are modified later, the thread's attributes are not affected. Upon successful completion, pthread_create() will store the ID of the created thread in the location specified by thread.

Upon its creation, the thread executes start_routine, with arg as its sole argument. If start_routine returns, the effect is as if there was an implicit call to pthread_exit(), using the return value of start_routine as the exit status. Note that the thread in which main() was originally invoked differs from this. When it returns from main(), the effect is as if there was an implicit call to exit(), using the return value of main() as the exit status.

Upon thread exit the storage for the thread must be reclaimed by another thread via a call to pthread_join(). Alternatively, pthread_detach() may be called on the thread to indicate that the system may automatically reclaim the thread storage upon exit. The pthread_attr_setdetachstate() function may be used on the attr argument passed to pthread_create() in order to achieve the same effect as a call to pthread_detach() on the newly created thread.

The signal state of the new thread is initialized as:

•   The signal mask is inherited from the creating thread.

•   The set of signals pending for the new thread is empty.

RETURN VALUES
If successful, the pthread_create() function will return zero. Otherwise, an error number will be returned to indicate the error.

ERRORS
pthread_create() will fail if:

[EAGAIN]
    The system lacked the necessary resources to create another thread, or the system-imposed limit on the total number of threads in a process [PTHREAD_THREADS_MAX] would be exceeded.

[EINVAL]
    The value specified by attr is invalid.

SEE ALSO
fork(2), pthread_cleanup_pop(3), pthread_cleanup_push(3), pthread_detach(3), pthread_exit(3), pthread_join(3)

STANDARDS
pthread_create() conforms to p1003.1-96.