PTHREAD_ATTR_GETGUARDSIZE(3) | Library Functions Manual | PTHREAD_ATTR_GETGUARDSIZE(3) |
pthread_attr_getguardsize
,
pthread_attr_setguardsize
—
#include <pthread.h>
int
pthread_attr_getguardsize
(const
pthread_attr_t * restrict attr,
size_t * restrict
guardsize);
int
pthread_attr_setguardsize
(pthread_attr_t
*attr, size_t
guardsize);
pthread_attr_getguardsize
() and
pthread_attr_setguardsize
() functions get and set
guardsize in the attr object. If
guardsize is larger than 0, the system reserves an
additional region of guarded memory of at least
guardsize bytes at the end of the thread's stack for
each new thread created by using attr.
The guarded area is understood to be pages of memory that are protected from read and write access. While the guarded area should be rounded by the system page size, the actual default size is implementation-defined. In NetBSD the default guardsize is given by the vm.thread_guard_size sysctl(7).
The rationale behind guardsize is two-fold:
SIGSEGV
signal or experience other comparable
fatal error condition. Note that if a thread allocates large data
structures on stack, it may be necessary to raise the default
guardsize in order to detect stack overflows.If pthread_attr_setstack(3) or pthread_attr_setstackaddr(3) is used to set the stack address attribute in attr, the guard size attribute is ignored and no guard area will be allocated; it is the responsibility of the application to handle the overflow conditions.
pthread_attr_getguardsize
().
The pthread_attr_setguardsize
() may fail
if:
ENOMEM
]July 2, 2017 | NetBSD 9.0 |