Professional Multicore Programming: Design and Implementation for C++ Developers

Name

NAME

pthread_equal — compare thread IDs

SYNOPSIS

THR #include <pthread.h>

    int pthread_equal(pthread_t tl, pthread_t t2);

DESCRIPTION

This function shall compare the thread IDs tl and t2.

RETURN VALUE

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

If either tl or t2 are not valid thread IDs, 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(), the Base Definitions volume of IEEE Std 1003.1-2001, <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.