http://pubs.opengroup.org/onlinepubs/7908799/xsh/pthread_create.html
NAME
pthread_create - thread creation
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() stores the ID of the created thread
in the location referenced by thread.
The thread is created executing start_routine with args 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.
The signal state of the new thread is initialised as follows:
The signal mask is inherited from the creating thread.
The set of signals pending for the new thread is empty.
If pthread_create() fails, no new thread is created
and the contents of the location referenced by thread are undefined.
RETURN VALUE
If successful, the pthread_create() function returns zero.
Otherwise, an error number is 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.
[EINVAL]
The value specified by attr is invalid.
[EPERM]
The caller does not have appropriate permission to set the required scheduling
parameters or scheduling policy.
The pthread_create() function will no return an error code of [EINTR].
EXAMPLES
None.
APPLICATION USAGE
None.
FUTURE DIRECTIONS
None.