From 300310ddc51a0022250a3b072f4c30c45470b857 Mon Sep 17 00:00:00 2001
From: Jean-Pierre PRUNARET <jean-pierre+git@prunetwork.fr>
Date: Thu, 19 Jan 2017 22:36:20 +0100
Subject: [PATCH] ajout code pour consruire un rand

---
 rand/main.c | 41 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/rand/main.c b/rand/main.c
index 7d59ee1..83ac801 100644
--- a/rand/main.c
+++ b/rand/main.c
@@ -1,3 +1,7 @@
+#define _POSIX_C_SOURCE 200809L
+
+#include <inttypes.h>
+#include <math.h>
 #include <time.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -18,12 +22,45 @@ int rand_lim(int limit) {
     return retval;
 }
 
+void print_current_time_with_ms (void) {
+    long            ms; // Milliseconds
+    time_t          s;  // Seconds
+    struct timespec spec;
+
+    clock_gettime(CLOCK_REALTIME, &spec);
+
+    s  = spec.tv_sec;
+    ms = round(spec.tv_nsec / 1.0e6); // Convert nanoseconds to milliseconds
+
+    printf  ( "Current time: %ld.%03ld seconds since the Epoch\n"
+            , (intmax_t)s
+            , ms
+            );
+}
+
+long int get_current_time_ms_part (void) {
+    long            milliseconds;
+    time_t          seconds;
+    struct timespec spec;
+
+    clock_gettime(CLOCK_REALTIME, &spec);
+
+    seconds  = spec.tv_sec;
+    milliseconds = round(spec.tv_nsec / 1.0e6); // Convert nanoseconds to milliseconds
+    return spec.tv_nsec;
+}
+
 int main(int argc, char **argv) {
-    srand(time(NULL));
+    /**
+     * time precision is 1 second. 2+ calls in same second return same value
+     */
+    //srand(time(NULL));
+    srand(get_current_time_ms_part());
 
     int random_value = rand_lim(1);
 
-    printf("value: %d\n", random_value);
+    //printf("value: %d\n", random_value);
+    printf("%d", random_value);
 
     //return rand_lim(1);
     return random_value;