oops, forgot to add sigio test program

trysigio.c

@@ -0,0 +1,39 @@
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <sys/poll.h>
+#include <signal.h>
+#include <fcntl.h>
+
+int main() {
+  int signum=SIGRTMIN+1;
+  sigset_t ss;
+  sigemptyset(&ss);
+  sigaddset(&ss,signum);
+  sigaddset(&ss,SIGIO);
+  sigprocmask(SIG_BLOCK,&ss,0);
+
+  fcntl(0 /* fd */,F_SETOWN,getpid());
+  fcntl(0 /* fd */,F_SETSIG,signum);
+#if defined(O_ONESIGFD) && defined(F_SETAUXFL)
+  fcntl(0 /* fd */, F_SETAUXFL, O_ONESIGFD);
+#endif
+  fcntl(0 /* fd */,F_SETFL,fcntl(0 /* fd */,F_GETFL)|O_NONBLOCK|O_ASYNC);
+
+  {
+    siginfo_t info;
+    struct timespec timeout;
+    int r;
+    timeout.tv_sec=1; timeout.tv_nsec=0;
+    switch ((r=sigtimedwait(&ss,&info,&timeout))) {
+    case SIGIO:
+      /* signal queue overflow */
+      signal(signum,SIG_DFL);
+      /* do poll */
+      break;
+    default:
+      if (r==signum) {
+	printf("event %c%c on fd #%d\n",info.si_band&POLLIN?'r':'-',info.si_band&POLLOUT?'w':'-',info.si_fd);
+      }
+    }
+  }
+}