Re: Is there such a thing as an invalid thread id?

On Thu, 19 Jan 2006 11:36:32 -0800, Buckaroo_Banzi wrote:

> I am creating a threaded application and just wish to return the thread
> id to the calling function. I am looking to let the calling function
> determine if pthread_create worked by the thread id.
>
> I have a feeling that there is a thread id value that indicates an
> invalid thread, such as 0 or -1. Could someone let me know if this is
> true and if so what value indicates an invalid thread?

>From the man page (gentle reminder to RTFM):

SYNOPSIS
#include <pthread.h>

int pthread_create(pthread_t * thread, pthread_attr_t * attr, void * (*start_routine)(void *), void *
arg);


DESCRIPTION
pthread_create creates a new thread of control that executes concurrently with the calling thread. The
new thread applies the function start_routine passing it arg as first argument. The new thread termi-
nates either explicitly, by calling pthread_exit(3), or implicitly, by returning from the start_routine
function. The latter case is equivalent to calling pthread_exit(3) with the result returned by
start_routine as exit code.

The attr argument specifies thread attributes to be applied to the new thread. See pthread_attr_init(3)
for a complete list of thread attributes. The attr argument can also be NULL, in which case default
attributes are used: the created thread is joinable (not detached) and has default (non real-time)
scheduling policy.


RETURN VALUE
On success, the identifier of the newly created thread is stored in the location pointed by the thread
argument, and a 0 is returned. On error, a non-zero error code is returned.


ERRORS
EAGAIN not enough system resources to create a process for the new thread.

EAGAIN more than PTHREAD_THREADS_MAX threads are already active.

.

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