PTHREAD_ATTR_GETSTACK(3P)                           POSIX Programmer's Manual                          PTHREAD_ATTR_GETSTACK(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       pthread_attr_getstack, pthread_attr_setstack - get and set stack attributes

SYNOPSIS
       #include <pthread.h>

       int pthread_attr_getstack(const pthread_attr_t *restrict attr,
              void **restrict stackaddr, size_t *restrict stacksize);
       int pthread_attr_setstack(pthread_attr_t *attr, void *stackaddr,
              size_t stacksize);




DESCRIPTION
       The  pthread_attr_getstack()  and  pthread_attr_setstack() functions, respectively, shall get and set the thread creation
       stack attributes stackaddr and stacksize in the attr object.

       The stack attributes specify the area of storage to be used for the created thread's stack. The base (lowest  addressable
       byte)  of the storage shall be stackaddr, and the size of the storage shall be stacksize bytes. The stacksize shall be at
       least {PTHREAD_STACK_MIN}.  The  stackaddr  shall  be  aligned  appropriately  to  be  used  as  a  stack;  for  example,
       pthread_attr_setstack()  may  fail  with [EINVAL] if ( stackaddr & 0x7) is not 0. All pages within the stack described by
       stackaddr and stacksize shall be both readable and writable by the thread.

RETURN VALUE
       Upon successful completion, these functions shall return a value of 0; otherwise, an error number shall  be  returned  to
       indicate the error.

       The pthread_attr_getstack() function shall store the stack attribute values in stackaddr and stacksize if successful.

ERRORS
       The pthread_attr_setstack() function shall fail if:

       EINVAL The value of stacksize is less than {PTHREAD_STACK_MIN} or exceeds an implementation-defined limit.


       The pthread_attr_setstack() function may fail if:

       EINVAL The  value of stackaddr does not have proper alignment to be used as a stack, or if ( stackaddr + stacksize) lacks
              proper alignment.

       EACCES The stack page(s) described by stackaddr and stacksize are not both readable and writable by the thread.


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

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       These functions are appropriate for use by applications in an environment where the stack for a thread must be placed  in
       some particular region of memory.

       While  it  might seem that an application could detect stack overflow by providing a protected page outside the specified
       stack region, this cannot be done portably. Implementations are free to place the thread's initial stack pointer anywhere
       within the specified region to accommodate the machine's stack pointer behavior and allocation requirements. Furthermore,
       on some architectures, such as the IA-64, "overflow" might mean that two separate stack  pointers  allocated  within  the
       region will overlap somewhere in the middle of the region.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       pthread_attr_init(),  pthread_attr_setdetachstate(),  pthread_attr_setstacksize(), pthread_create(), the Base Definitions
       volume of IEEE Std 1003.1-2001, <limits.h>, <pthread.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy  between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group
       Standard  is  the  referee   document.   The   original   Standard   can   be   obtained   online   at   http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                     PTHREAD_ATTR_GETSTACK(3P)