Sistemi operativi - Syscall pthread_create

pthread_create

The Single UNIX ® Specification, Version 2

Copyright © 1997 The Open Group

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 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.

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.