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.