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



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

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 pthread__attr__setstack() function may fail with [EINVAL] if
       stackaddr does not meet implementation-defined alignment requirements.
       All pages within the stack described by stackaddr and stacksize shall
       be both readable and writable by the thread.

       If the pthread__attr__getstack() function is called before the stackaddr
       attribute has been set, the behavior is unspecified.

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

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 (char **)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.

       After a successful call to pthread__attr__setstack(), the storage area
       specified by the stackaddr parameter is under the control of the
       implementation, as described in Section 2.9.8, Use of Application-
       Managed Thread Stacks.

       The specification of the stackaddr attribute presents several
       ambiguities that make portable use of these functions impossible. For
       example, the standard allows implementations to impose arbitrary
       alignment requirements on stackaddr.  Applications cannot assume that a
       buffer obtained from malloc() is suitably aligned. Note that although
       the stacksize value passed to pthread__attr__setstack() must satisfy
       alignment requirements, the same is not true for
       pthread__attr__setstacksize() where the implementation must increase the
       specified size if necessary to achieve the proper alignment.

RATIONALE
       If an implementation detects that the value specified by the attr
       argument to pthread__attr__getstack() or pthread__attr__setstack() 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__getdetachstate(),
       pthread__attr__getstacksize(), pthread__create()

       The Base Definitions volume of POSIX.1-2017, <limits.h>, <pthread.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017             PTHREAD_ATTR_GETSTACK(3)
