2 * Find out the size of kernel's sigset_t.
4 * Copyright (c) 2016-2017 Dmitry V. Levin <ldv@altlinux.org>
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33 #include <asm/unistd.h>
36 * If the sigset size specified to rt_sigprocmask is not equal to the size
37 * of kernel's sigset_t, the kernel does not look at anything else and fails
40 * Otherwise, if both pointers specified to rt_sigprocmask are NULL,
41 * the kernel just returns 0.
43 * This vaguely documented kernel feature can be used to probe
44 * the kernel and find out the size of kernel's sigset_t.
50 static unsigned int set_size;
53 static const unsigned int big_size = 1024 / 8;
55 for (set_size = big_size; set_size; set_size >>= 1) {
56 if (!syscall(__NR_rt_sigprocmask, SIG_SETMASK,
57 NULL, NULL, set_size))
62 perror_msg_and_fail("rt_sigprocmask");