|PTHREAD_ATTR_SETGUARDSIZE(3)||Linux Programmer's Manual||PTHREAD_ATTR_SETGUARDSIZE(3)|
int pthread_attr_setguardsize(pthread_attr_t *attr, size_t guardsize); int pthread_attr_getguardsize(const pthread_attr_t *restrict attr, size_t *restrict guardsize);
Compile and link with -pthread.
If guardsize is greater than 0, then for each new thread created using attr the system allocates an additional region of at least guardsize bytes at the end of the thread's stack to act as the guard area for the stack (but see BUGS).
If guardsize is 0, then new threads created with attr will not have a guard area.
The default guard size is the same as the system page size.
If the stack address attribute has been set in attr (using pthread_attr_setstack(3) or 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 mprotect(2) to manually define a guard area at the end of the stack that it has allocated).
The pthread_attr_getguardsize() function returns the guard size attribute of the thread attributes object referred to by attr in the buffer pointed to by guardsize.
|pthread_attr_setguardsize (), pthread_attr_getguardsize ()||Thread safety||MT-Safe|
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.
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.
The obsolete LinuxThreads implementation did the right thing, allocating extra space at the end of the stack for the guard area.