| Standards / Extensions | C or C++ | Dependencies |
|---|---|---|
Single UNIX Specification, Version 3 |
both | z/OS V1R9 |
#define _UNIX03_THREADS
#include <pthread.h>
int pthread_attr_setguardsize(pthread_attr_t *attr, size_t guardsize);pthread_attr_setguardsize() sets the guardsize attribute in attr using the value of guardsize.
attr is a pointer to a thread attribute object initialized by pthread_attr_init().
This function stores the guardsize attribute in the thread attribute object for subsequent calls to pthread_attr_getguardsize(), but no further action is taken. The guardsize attribute is ignored during thread creation.
The Single UNIX Specification, Version 3 expects a guard area of at least guardsize bytes, but permits the rounding of guardsize to a multiple of the system variable, PAGESIZE. Stack management in z/OS® UNIX sets a guard area of PAGESIZE in 31-bit applications and of (PAGESIZE * PAGESIZE) bytes in AMODE64. These values are the default for the guard size attribute. Requests for larger guard areas will fail with EINVAL.
A zero guardsize requests that no guard area be provided. However, z/OS UNIX stack management requires a guard area. Therefore, this request cannot be satisfied, although pthread_attr_setguardsize() will tolerate a guardsize of zero.
If successful, pthread_attr_setguardsize() returns 0; otherwise, it returns an error number.
⁄* CELEBP66 *⁄
⁄* Example using SUSv3 pthread_attr_setguardsize() interface *⁄
#define _XOPEN_SOURCE 600
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <limits.h>
#include <errno.h>
int main(void)
{
pthread_attr_t attr;
int rc;
if (pthread_attr_init(&attr) == -1) {
perror("error in pthread_attr_init");
exit(1);
}
printf("Set guardsize to value of PAGESIZE.\n");
rc = pthread_attr_setguardsize(&attr, PAGESIZE);
if (rc != 0) {
printf("pthread_attr_setguardsize returned: %d\n", rc);
printf("Error: %d, Errno_Jr: %08x\n", errno, __errno2());
exit(2);
} else {
printf("Set guardsize is %d\n", PAGESIZE);
}
rc = pthread_attr_destroy(&attr);
if (rc != 0) {
perror("error in pthread_attr_destroy");
exit(3);
}
exit(0);
}