From 79fc63135bf4073dde51466eafea3a524c0b99f8 Mon Sep 17 00:00:00 2001
From: Sergiusz Warga <sergiusz.warga@pwr.edu.pl>
Date: Wed, 10 Mar 2021 22:08:21 +0100
Subject: [PATCH] Excahnged clock() with gettimeofday()

---
 .gitignore         |  3 +++
 Topic-2/task_2_4.c | 28 +++++++++++++++++-----------
 2 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/.gitignore b/.gitignore
index 9324439..89d6c6e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,6 @@ cmake-build-debug
 CMakeLists.txt
 .idea
 *.o
+
+# Apple
+.DS_Store
\ No newline at end of file
diff --git a/Topic-2/task_2_4.c b/Topic-2/task_2_4.c
index 8c89ad3..d4e233f 100644
--- a/Topic-2/task_2_4.c
+++ b/Topic-2/task_2_4.c
@@ -4,11 +4,20 @@
 
 #include <stdio.h>
 #include <sys/types.h>
+#include <sys/time.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <signal.h>
 #include <time.h>
 
+const char * time_from_main_exec() {
+    struct timeval now;
+    gettimeofday(&now, NULL);
+    char buff[127];
+    sprintf(&buff, "us : %d", now.tv_usec);
+    return buff;
+}
+
 void parent_before_child() {
     pid_t pid;
     printf("\nparent_before_child()\n");
@@ -18,11 +27,11 @@ void parent_before_child() {
         exit(EXIT_FAILURE);
     }
     if (pid != 0) {     // If this is a parent process.
-        printf("===\nI am a parent.\nMy PID is: %d\n===", getpid());
+        printf("===\n%s\nI am a parent.\nMy PID is: %d\n===", time_from_main_exec(), getpid());
         kill(getpid(), SIGTERM);
     } else {
         sleep(1);
-        printf("===\nI am a child.\nMy PID is: %d\n===", getpid()); // This line will not be printed, as (usually) parent process will finish
+        printf("===\n%s\nI am a child.\nMy PID is: %d\n===", time_from_main_exec(), getpid()); // This line will not be printed, as (usually) parent process will finish
         // its execution in less than 1 second
     }
 }
@@ -37,31 +46,28 @@ void child_before_parent() {
         exit(EXIT_FAILURE);
     }
     if (pid == 0) {     // If this is a parent process.
-        printf("===\nI am a child.\nMy PID is: %d\n===", getpid());
+        printf("===\n%s\nI am a child.\nMy PID is: %d\n===", time_from_main_exec(), getpid());
         kill(getpid(), SIGTERM);
     } else {
         sleep(1);
-        printf("===\nI am a parent.\nMy PID is: %d\n===", getpid());
+        printf("===\n%s\nI am a parent.\nMy PID is: %d\n===", time_from_main_exec(), getpid());
     }
 }
 
-double time_from_exec(clock_t begin) {
-    return (double)(clock() - begin)/CLOCKS_PER_SEC;
-}
 
 int main() {
-    clock_t begin = clock();
+    
     pid_t pid;
-    printf("%f: Grandparent process has PID: %d\n", time_from_exec(begin), getpid());
+    printf("%s: Grandparent process has PID: %d\n", time_from_main_exec(), getpid());
     pid = fork();
     if (pid == 0) { // If child process
-        printf("%f: Process with PID %d will execute funs.\n", time_from_exec(begin), getpid());
+        printf("%s: Process with PID %d will execute funs.\n", time_from_main_exec(), getpid());
         child_before_parent();
         sleep(1);
         parent_before_child();
         sleep(1);
     } else {        // If parent process
-        printf("%f: Grandparent's child process has PID: %d\n", time_from_exec(begin), pid);
+        printf("%s: Grandparent's child process has PID: %d\n", time_from_main_exec(), pid);
         sleep(5);
     }
     return 0;