PTHREAD_ATTR_GETSTACK(3P) POSIX Programmer's Manual PTHREAD_ATTR_GETSTACK(3P)
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This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult 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 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
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 environ-
ment 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 accommo-
date 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 imple-
mentation, as described in Section 2.9.8, Use of Application-Managed
Thread Stacks.
The specification of the stackaddr attribute presents several ambigui-
ties 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 align-
ment 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 argu-
ment 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.1-2008, <limits.h>, <pthread.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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.ker-
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 PTHREAD_ATTR_GETSTACK(3P)
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