OrionLibC

#include <sys/syscall.h>
#include <signal.h>
#include <errno.h>

/* Send a signal to a process */
int
sigprocmask(int how, const sigset_t *set, sigset_t *oldset)
{
	int ret;
	asm volatile("int $0x80" : "=a" (ret) : "0" (SYSCALL_SIGPROCMASK),
	             "c" (3), "S" (&how));
	if (ret >= 0)
		return ret;
	errno = -ret;
	return -1;
}