NAME

pthread_attr_getdetachstate, pthread_attr_setdetachstate — get and set the detachstate attribute

SYNOPSIS

#include <pthread.h>

int pthread_attr_getdetachstate(const pthread_attr_t *attr,
       int *detachstate);
int pthread_attr_setdetachstate(pthread_attr_t *attr, int detachstate);


DESCRIPTION

The detachstate attribute controls whether the thread is created in a detached state. If the thread is created detached, then use of the ID of the newly created thread by the pthread_detach() or pthread_join() function is an error.

The pthread_attr_getdetachstate() and pthread_attr_setdetachstate() functions, respectively, shall get and set the detachstate attribute in the attr object.

For pthread_attr_getdetachstate(), detachstate shall be set to either PTHREAD_CREATE_DETACHED or PTHREAD_CREATE_JOINABLE.

For pthread_attr_setdetachstate(), the application shall set detachstate to either PTHREAD_CREATE_DETACHED or PTHREAD_CREATE_JOINABLE.

A value of PTHREAD_CREATE_DETACHED shall cause all threads created with attr to be in the detached state, whereas using a value of PTHREAD_CREATE_JOINABLE shall cause all threads created with attr to be in the joinable state. The default value of the detachstate attribute shall be PTHREAD_CREATE_JOINABLE.

The behavior is undefined if the value specified by the attr argument to pthread_attr_getdetachstate() or pthread_attr_setdetachstate() does not refer to an initialized thread attributes object.

RETURN VALUE

Upon successful completion, pthread_attr_getdetachstate() and pthread_attr_setdetachstate() shall return a value of 0; otherwise, an error number shall be returned to indicate the error.

The pthread_attr_getdetachstate() function stores the value of the detachstate attribute in detachstate if successful.

ERRORS

The pthread_attr_setdetachstate() function shall fail if:

[EINVAL]

The value of detachstate was not valid

These functions shall not return an error code of [EINTR].

EXAMPLES

Retrieving the detachstate Attribute

This example shows how to obtain the detachstate attribute of a thread attribute object.

#include <pthread.h>


pthread_attr_t thread_attr;
int            detachstate;
int            rc;


/* code initializing thread_attr */
...


rc = pthread_attr_getdetachstate (&thread_attr, &detachstate);
if (rc!=0) {
    /* handle error */
    ...
}
else {
    /* legal values for detachstate are:
     * PTHREAD_CREATE_DETACHED or PTHREAD_CREATE_JOINABLE
     */
     ...
}

APPLICATION USAGE

None.

RATIONALE

If an implementation detects that the value specified by the attr argument to pthread_attr_getdetachstate() or pthread_attr_setdetachstate() does not refer to an initialized thread attributes object, it is recommended that the function should fail and report an [EINVAL] error.

FUTURE DIRECTIONS

None.

SEE ALSO

pthread_attr_destroy, pthread_attr_getstacksize, pthread_create

XBD <pthread.h>

CHANGE HISTORY

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

Issue 6

The pthread_attr_setdetachstate() and pthread_attr_getdetachstate() functions are marked as part of the Threads option.

The normative text is updated to avoid use of the term "must" for application requirements.

IEEE Std 1003.1-2001/Cor 2-2004, item XSH/TC2/D6/72 is applied, adding the example to the EXAMPLES section.

IEEE Std 1003.1-2001/Cor 2-2004, item XSH/TC2/D6/73 is applied, updating the ERRORS section to include the optional [EINVAL] error.

Issue 7

The pthread_attr_setdetachstate() and pthread_attr_getdetachstate() functions are moved from the Threads option to the Base.

The [EINVAL] error for an uninitialized thread attributes object is removed; this condition results in undefined behavior.