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 (consult the correspond-
       ing 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 stor-
       age 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, "over-
       flow" 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 Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (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.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003						 PTHREAD_ATTR_GETSTACK(3P)