1 files changed, 63 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/OR_USING_C/nap.c b/reference/C/CONTRIB/OR_USING_C/nap.c
new file mode 100644
index 0000000..09f4a74
--- /dev/null
+++ b/reference/C/CONTRIB/OR_USING_C/nap.c
@@ -0,0 +1,63 @@
+#include <sys/time.h>
+#include <signal.h>
+
+#define setvec(vec, a) \
+            vec.sv_handler = a; \
+            vec.sv_mask = vec.sv_flags = 0
+
+static int ringring;
+
+nap(n)
+unsigned n;
+{
+    void napx();
+    int omask;
+    struct sigvec vec, ovec;
+    struct itimerval itv, oitv;
+    register struct itimerval *itp = &itv;
+
+    if (n == 0)
+        return;
+    timerclear(&itp->it_interval);
+    timerclear(&itp->it_value);
+    if (setitimer(ITIMER_REAL, itp, &oitv) < 0)
+        return;
+    setvec(ovec, SIG_DFL);
+    omask = sigblock(sigmask(SIGALRM));
+    itp->it_value.tv_sec = n/60;
+    itp->it_value.tv_usec = (n%60)*1000000/60;
+    if (timerisset(&oitv.it_value)) {
+        if (oitv.it_value.tv_sec >= itp->it_value.tv_sec) {
+            if (oitv.it_value.tv_sec == itp->it_value.tv_sec &&
+                oitv.it_value.tv_usec > itp->it_value.tv_usec)
+                oitv.it_value.tv_usec -= itp->it_value.tv_usec;
+                    oitv.it_value.tv_sec -= itp->it_value.tv_sec;
+        }
+        else {
+            itp->it_value = oitv.it_value;
+            /*
+             * This is a hack, but we must have time to return from 
+             * the setitimer after the alarm or else it will restart.
+             * And, anyway, sleep never did more than this before.
+             */
+            oitv.it_value.tv_sec = 1;
+            oitv.it_value.tv_usec = 0;
+        }
+    }
+    setvec(vec, napx);
+    ringring = 0;
+    sigvec(SIGALRM, &vec, &ovec);
+    setitimer(ITIMER_REAL, itp, (struct itimerval *)0);
+    while (!ringring)
+        sigpause(omask &~ sigmask(SIGALRM));
+    sigvec(SIGALRM, &ovec, (struct sigvec *)0);
+    setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0);
+    sigsetmask(omask);
+}
+
+static void
+napx()
+{
+    ringring = 1;
+}
+