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Diffstat (limited to 'man3/pthread_attr_setguardsize.3')
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diff --git a/man3/pthread_attr_setguardsize.3 b/man3/pthread_attr_setguardsize.3 deleted file mode 100644 index de9e4f2b7..000000000 --- a/man3/pthread_attr_setguardsize.3 +++ /dev/null @@ -1,163 +0,0 @@ -'\" t -.\" Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk -.\" <mtk.manpages@gmail.com> -.\" -.\" SPDX-License-Identifier: Linux-man-pages-copyleft -.\" -.TH pthread_attr_setguardsize 3 (date) "Linux man-pages (unreleased)" -.SH NAME -pthread_attr_setguardsize, pthread_attr_getguardsize \- set/get guard size -attribute in thread attributes object -.SH LIBRARY -POSIX threads library -.RI ( libpthread ", " \-lpthread ) -.SH SYNOPSIS -.nf -.B #include <pthread.h> -.P -.BI "int pthread_attr_setguardsize(pthread_attr_t *" attr \ -", size_t " guardsize ); -.BI "int pthread_attr_getguardsize(const pthread_attr_t *restrict " attr , -.BI " size_t *restrict " guardsize ); -.fi -.SH DESCRIPTION -The -.BR pthread_attr_setguardsize () -function sets the guard size attribute of the -thread attributes object referred to by -.I attr -to the value specified in -.IR guardsize . -.P -If -.I guardsize -is greater than 0, -then for each new thread created using -.I attr -the system allocates an additional region of at least -.I guardsize -bytes at the end of the thread's stack to act as the guard area -for the stack (but see BUGS). -.P -If -.I guardsize -is 0, then new threads created with -.I attr -will not have a guard area. -.P -The default guard size is the same as the system page size. -.P -If the stack address attribute has been set in -.I attr -(using -.BR pthread_attr_setstack (3) -or -.BR pthread_attr_setstackaddr (3)), -meaning that the caller is allocating the thread's stack, -then the guard size attribute is ignored -(i.e., no guard area is created by the system): -it is the application's responsibility to handle stack overflow -(perhaps by using -.BR mprotect (2) -to manually define a guard area at the end of the stack -that it has allocated). -.P -The -.BR pthread_attr_getguardsize () -function returns the guard size attribute of the -thread attributes object referred to by -.I attr -in the buffer pointed to by -.IR guardsize . -.SH RETURN VALUE -On success, these functions return 0; -on error, they return a nonzero error number. -.SH ERRORS -POSIX.1 documents an -.B EINVAL -error if -.I attr -or -.I guardsize -is invalid. -On Linux these functions always succeed -(but portable and future-proof applications should nevertheless -handle a possible error return). -.SH ATTRIBUTES -For an explanation of the terms used in this section, see -.BR attributes (7). -.TS -allbox; -lbx lb lb -l l l. -Interface Attribute Value -T{ -.na -.nh -.BR pthread_attr_setguardsize (), -.BR pthread_attr_getguardsize () -T} Thread safety MT-Safe -.TE -.SH STANDARDS -POSIX.1-2008. -.SH HISTORY -glibc 2.1. -POSIX.1-2001. -.SH NOTES -A guard area consists of virtual memory pages that are protected -to prevent read and write access. -If a thread overflows its stack into the guard area, -then, on most hard architectures, it receives a -.B SIGSEGV -signal, thus notifying it of the overflow. -Guard areas start on page boundaries, -and the guard size is internally rounded up to -the system page size when creating a thread. -(Nevertheless, -.BR pthread_attr_getguardsize () -returns the guard size that was set by -.BR pthread_attr_setguardsize ().) -.P -Setting a guard size of 0 may be useful to save memory -in an application that creates many threads -and knows that stack overflow can never occur. -.P -Choosing a guard size larger than the default size -may be necessary for detecting stack overflows -if a thread allocates large data structures on the stack. -.SH BUGS -As at glibc 2.8, the NPTL threading implementation includes -the guard area within the stack size allocation, -rather than allocating extra space at the end of the stack, -as POSIX.1 requires. -(This can result in an -.B EINVAL -error from -.BR pthread_create (3) -if the guard size value is too large, -leaving no space for the actual stack.) -.P -The obsolete LinuxThreads implementation did the right thing, -allocating extra space at the end of the stack for the guard area. -.\" glibc includes the guardsize within the allocated stack size, -.\" which looks pretty clearly to be in violation of POSIX. -.\" -.\" Filed bug, 22 Oct 2008: -.\" https://www.sourceware.org/bugzilla/show_bug.cgi?id=6973 -.\" -.\" Older reports: -.\" https//bugzilla.redhat.com/show_bug.cgi?id=435337 -.\" Reportedly, LinuxThreads did the right thing, allocating -.\" extra space at the end of the stack: -.\" http://sourceware.org/ml/libc-alpha/2008-05/msg00086.html -.SH EXAMPLES -See -.BR pthread_getattr_np (3). -.SH SEE ALSO -.BR mmap (2), -.BR mprotect (2), -.BR pthread_attr_init (3), -.BR pthread_attr_setstack (3), -.BR pthread_attr_setstacksize (3), -.BR pthread_create (3), -.BR pthreads (7) |