NAME
pthreadattrsetstack, pthreadattrgetstack - set/get stack attributes in thread attributes object SYNOPSIS
#include
int pthreadattrsetstack(pthreadattrt *attr, void *stackaddr, sizet stacksize); int pthreadattrgetstack(pthreadattrt *attr, void **stackaddr, sizet *stacksize); Compile and link with -pthread. Feature Test Macro Requirements for glibc (see featuretestmacros(7)): pthreadattrgetstack(), pthreadattrsetstack(): POSIXCSOURCE >= 200112L || XOPENSOURCE >= 600 DESCRIPTION The pthreadattrsetstack() function sets the stack address and stack size attributes of the thread attributes object referred to by attr to the values specified in stackaddr and stacksize, respectively. These attributes specify the location and size of the stack that should be used by a thread that is created using the thread attributes object attr. stackaddr should point to the lowest addressable byte of a buffer of stacksize bytes that was allocated by the caller. The pages of the allocated buffer should be both readable and writable. The pthreadattrgetstack() function returns the stack address and stack size attributes of the thread attributes object referred to by attr in the buffers pointed to by stackaddr and stacksize, respec‐ tively. RETURN VALUE On success, these functions return 0; on error, they return a nonzero error number. ERRORS pthreadattrsetstack() can fail with the following error: EINVAL stacksize is less than PTHREADSTACKMIN (16384) bytes. On some systems, this error may also occur if stackaddr or stack‐ addr + stacksize is not suitably aligned.
POSIX.1-2001 also documents an EACCES error if the stack area described by stackaddr and stacksize is not both readable and writable by the caller. VERSIONS These functions are provided by glibc since version 2.2. ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). ┌─────────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├─────────────────────────┼───────────────┼─────────┤
│pthreadattrsetstack(), │ Thread safety │ MT-Safe │ │pthreadattrgetstack() │ │ │ └─────────────────────────┴───────────────┴─────────┘ CONFORMING TO
POSIX.1-2001. NOTES These functions are provided for applications that must ensure that a thread's stack is placed in a particular location. For most applica‐ tions, this is not necessary, and the use of these functions should be avoided. (Use pthreadattrsetstacksize(3) if an application simply requires a stack size other than the default.) When an application employs pthreadattrsetstack(), it takes over the responsibility of allocating the stack. Any guard size value that was set using pthreadattrsetguardsize(3) is ignored. If deemed neces‐ sary, it is the application's responsibility to allocate a guard area (one or more pages protected against reading and writing) to handle the possibility of stack overflow. The address specified in stackaddr should be suitably aligned: for full portability, align it on a page boundary (sysconf(SCPAGESIZE)). posixmemalign(3) may be useful for allocation. Probably, stacksize should also be a multiple of the system page size. If attr is used to create multiple threads, then the caller must change the stack address attribute between calls to pthreadcreate(3); other‐ wise, the threads will attempt to use the same memory area for their stacks, and chaos will ensue. EXAMPLE See pthreadattrinit(3). SEE ALSO mmap(2), mprotect(2), posixmemalign(3), pthreadattrinit(3), pthreadattrsetguardsize(3), pthreadattrsetstackaddr(3), pthreadattrsetstacksize(3), pthreadcreate(3), pthreads(7) COLOPHON
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Linux 2008-10-24 PTHREADATTRSETSTACK(3)