pthread_attr_getstack.3p (5935B)
- '\" et
- .TH PTHREAD_ATTR_GETSTACK "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
- .\"
- .SH PROLOG
- 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.
- .\"
- .SH NAME
- pthread_attr_getstack,
- pthread_attr_setstack
- \(em get and set stack attributes
- .SH SYNOPSIS
- .LP
- .nf
- #include <pthread.h>
- .P
- int pthread_attr_getstack(const pthread_attr_t *restrict \fIattr\fP,
- void **restrict \fIstackaddr\fP, size_t *restrict \fIstacksize\fP);
- int pthread_attr_setstack(pthread_attr_t *\fIattr\fP, void *\fIstackaddr\fP,
- size_t \fIstacksize\fP);
- .fi
- .SH DESCRIPTION
- The
- \fIpthread_attr_getstack\fR()
- and
- \fIpthread_attr_setstack\fR()
- functions, respectively, shall get and set the thread creation stack
- attributes
- .IR stackaddr
- and
- .IR stacksize
- in the
- .IR attr
- object.
- .P
- 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
- .IR stackaddr ,
- and the size of the storage shall be
- .IR stacksize
- bytes. The
- .IR stacksize
- shall be at least
- {PTHREAD_STACK_MIN}.
- The
- \fIpthread_attr_setstack\fR()
- function may fail with
- .BR [EINVAL]
- if
- .IR stackaddr
- does not meet implementation-defined alignment requirements.
- All pages within the stack described by
- .IR stackaddr
- and
- .IR stacksize
- shall be both readable and writable by the thread.
- .P
- If the
- \fIpthread_attr_getstack\fR()
- function is called before the
- .IR stackaddr
- attribute has been set, the behavior is unspecified.
- .P
- The behavior is undefined if the value specified by the
- .IR attr
- argument to
- \fIpthread_attr_getstack\fR()
- or
- \fIpthread_attr_setstack\fR()
- does not refer to an initialized thread attributes object.
- .SH "RETURN VALUE"
- Upon successful completion, these functions shall return a value of 0;
- otherwise, an error number shall be returned to indicate the error.
- .P
- The
- \fIpthread_attr_getstack\fR()
- function shall store the stack attribute values in
- .IR stackaddr
- and
- .IR stacksize
- if successful.
- .SH ERRORS
- .P
- The
- \fIpthread_attr_setstack\fR()
- function shall fail if:
- .TP
- .BR EINVAL
- The value of
- .IR stacksize
- is less than
- {PTHREAD_STACK_MIN}
- or exceeds an implementation-defined limit.
- .P
- The
- \fIpthread_attr_setstack\fR()
- function may fail if:
- .TP
- .BR EINVAL
- The value of
- .IR stackaddr
- does not have proper alignment to be used as a stack, or ((\c
- .BR "char *" )\c
- .IR stackaddr
- +
- .IR stacksize )
- lacks proper alignment.
- .TP
- .BR EACCES
- The stack page(s) described by
- .IR stackaddr
- and
- .IR stacksize
- are not both readable and writable by the thread.
- .P
- These functions shall not return an error code of
- .BR [EINTR] .
- .LP
- .IR "The following sections are informative."
- .SH EXAMPLES
- None.
- .SH "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.
- .P
- 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\(hy64,
- ``overflow'' might mean that two separate stack pointers allocated
- within the region will overlap somewhere in the middle of the region.
- .P
- After a successful call to
- \fIpthread_attr_setstack\fR(),
- the storage area specified by the
- .IR stackaddr
- parameter is under the control of the implementation, as described in
- .IR "Section 2.9.8" ", " "Use of Application-Managed Thread Stacks".
- .P
- The specification of the
- .IR 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
- .IR stackaddr .
- Applications cannot assume that a buffer obtained from
- \fImalloc\fR()
- is suitably aligned. Note that although the
- .IR stacksize
- value passed to
- \fIpthread_attr_setstack\fR()
- must satisfy alignment requirements, the same is not true for
- \fIpthread_attr_setstacksize\fR()
- where the implementation must increase the specified size if
- necessary to achieve the proper alignment.
- .SH RATIONALE
- If an implementation detects that the value specified by the
- .IR attr
- argument to
- \fIpthread_attr_getstack\fR()
- or
- \fIpthread_attr_setstack\fR()
- does not refer to an initialized thread attributes object, it is
- recommended that the function should fail and report an
- .BR [EINVAL]
- error.
- .SH "FUTURE DIRECTIONS"
- None.
- .SH "SEE ALSO"
- .ad l
- .IR "\fIpthread_attr_destroy\fR\^(\|)",
- .IR "\fIpthread_attr_getdetachstate\fR\^(\|)",
- .IR "\fIpthread_attr_getstacksize\fR\^(\|)",
- .IR "\fIpthread_create\fR\^(\|)"
- .ad b
- .P
- The Base Definitions volume of POSIX.1\(hy2017,
- .IR "\fB<limits.h>\fP",
- .IR "\fB<pthread.h>\fP"
- .\"
- .SH 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 .
- .PP
- 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 .