NAME
pthread_create —
create a new thread
SYNOPSIS
#include
<pthread.h>
int
pthread_create(pthread_t
*thread, const
pthread_attr_t *attr,
void *(*start_routine)(void
*), void *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.
The thread is created executing
start_routine with arg as its
sole argument. If the 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
The pthread_create() function 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.
- [
EPERM] - The caller does not have appropriate permission to set the required scheduling parameters or scheduling policy.
- [
EINVAL] - The value specified by attr is invalid.
SEE ALSO
fork(2), pthread_attr(3), pthread_cancel(3), pthread_cleanup_pop(3), pthread_cleanup_push(3), pthread_exit(3), pthread_join(3)
STANDARDS
The pthread_create() function conforms to
ISO/IEC 9945-1:1996 (“POSIX.1”).