NAME

pthread_attr_getstackaddr, pthread_attr_setstackaddr - get and set the stackaddr attribute

SYNOPSIS

[THR TSA] #include <pthread.h>



[OB] int pthread_attr_getstackaddr(const pthread_attr_t *restrict attr,
       void **restrict stackaddr);
int pthread_attr_setstackaddr(pthread_attr_t *attr, void *stackaddr);

DESCRIPTION

The pthread_attr_getstackaddr() and pthread_attr_setstackaddr() functions, respectively, shall get and set the thread creation stackaddr attribute in the attr object.

The stackaddr attribute specifies the location of storage to be used for the created thread's stack. The size of the storage shall be at least {PTHREAD_STACK_MIN}.

RETURN VALUE

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

The pthread_attr_getstackaddr() function stores the stackaddr attribute value in stackaddr if successful.

ERRORS

These functions may fail if:

[EINVAL]

The value specified by attr does not refer to an initialized thread attribute object.

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

EXAMPLES

None.

APPLICATION USAGE

The specification of the stackaddr attribute presents several ambiguities that make portable use of these interfaces impossible. The description of the single address parameter as a "stack" does not specify a particular relationship between the address and the "stack" implied by that address. For example, the address may be taken as the low memory address of a buffer intended for use as a stack, or it may be taken as the address to be used as the initial stack pointer register value for the new thread. These two are not the same except for a machine on which the stack grows "up" from low memory to high, and on which a "push" operation first stores the value in memory and then increments the stack pointer register. Further, on a machine where the stack grows "down" from high memory to low, interpretation of the address as the "low memory" address requires a determination of the intended size of the stack. IEEE Std 1003.1-2001 has introduced the new interfaces pthread_attr_setstack() and pthread_attr_getstack() to resolve these ambiguities.

After a successful call to pthread_attr_setstackaddr(), the storage area specified by the stackaddr parameter is under the control of the implementation, as described in Use of Application-Managed Thread Stacks.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

pthread_attr_destroy(), pthread_attr_getdetachstate(), pthread_attr_getstack(), pthread_attr_getstacksize(), pthread_attr_setstack(), pthread_create(), the Base Definitions volume of IEEE Std 1003.1-2001, <limits.h>, <pthread.h>

CHANGE HISTORY

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

Issue 6

The pthread_attr_getstackaddr() and pthread_attr_setstackaddr() functions are marked as part of the Threads and Thread Stack Address Attribute options.

The restrict keyword is added to the pthread_attr_getstackaddr() prototype for alignment with the ISO/IEC 9899:1999 standard.

These functions are marked obsolescent.

IEEE Std 1003.1-2001/Cor 2-2004, item XSH/TC2/D6/85 is applied, updating the APPLICATION USAGE section to refer to Use of Application-Managed Thread Stacks.

IEEE Std 1003.1-2001/Cor 2-2004, item XSH/TC2/D6/86 is applied, updating the ERRORS section to include optional errors for the case when attr refers to an uninitialized thread attribute object.