NAME

pthread_equal — compare thread IDs

SYNOPSIS

#include <pthread.h>

int pthread_equal(pthread_t t1, pthread_t t2);


DESCRIPTION

This function shall compare the thread IDs t1 and t2.

RETURN VALUE

The pthread_equal() function shall return a non-zero value if t1 and t2 are equal; otherwise, zero shall be returned.

If either t1 or t2 is not a valid thread ID and is not equal to PTHREAD_NULL, the behavior is undefined.

ERRORS

No errors are defined.

The pthread_equal() function shall not return an error code of [EINTR].

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

Implementations may choose to define a thread ID as a structure. This allows additional flexibility and robustness over using an int. For example, a thread ID could include a sequence number that allows detection of "dangling IDs" (copies of a thread ID that has been detached). Since the C language does not support comparison on structure types, the pthread_equal() function is provided to compare thread IDs.

FUTURE DIRECTIONS

None.

SEE ALSO

pthread_create, pthread_self

XBD <pthread.h>

CHANGE HISTORY

First released in Issue 5. Included for alignment with the POSIX Threads Extension.

Issue 6

The pthread_equal() function is marked as part of the Threads option.

Issue 7

The pthread_equal() function is moved from the Threads option to the Base.

Issue 8

Austin Group Defect 599 is applied, changing the RETURN VALUE section to mention PTHREAD_NULL.