From 962ee7180ea70430ccaf0446ea82610b5d9f506e Mon Sep 17 00:00:00 2001
From: MAO Dongyang <suchcp@gmail.com>
Date: Wed, 22 Mar 2023 16:03:42 +0100
Subject: [PATCH] SIGNAL

---
 System2/catch_signal/main.c  | 23 +++++++++++++++++++++++
 System2/create_ps/main.c     |  3 +--
 System2/example_alarm/main.c | 21 +++++++++++++++++++++
 System2/sendToFile/main.c    | 23 +++++++++++++++++++++++
 System2/sendToFile/test.txt  |  0
 TP3/List/main.c              |  1 -
 6 files changed, 68 insertions(+), 3 deletions(-)
 create mode 100644 System2/catch_signal/main.c
 create mode 100644 System2/example_alarm/main.c
 create mode 100644 System2/sendToFile/main.c
 create mode 100644 System2/sendToFile/test.txt

diff --git a/System2/catch_signal/main.c b/System2/catch_signal/main.c
new file mode 100644
index 0000000..e318e0e
--- /dev/null
+++ b/System2/catch_signal/main.c
@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <signal.h>
+#include <unistd.h>
+
+void sig_usr(int signo)
+{
+    if (signo == SIGUSR1)
+        printf("received SIGUSR1\n");
+    else if (signo == SIGUSR2)
+        printf("received SIGUSR2\n");
+    else
+        printf("received signal %d\n", signo);
+}
+
+int main(void)
+{
+    if (signal(SIGUSR1, sig_usr) == SIG_ERR)
+        printf("can't catch SIGUSR1\n");
+    if (signal(SIGUSR2, sig_usr) == SIG_ERR)
+        printf("can't catch SIGUSR2\n");
+    for (;;)
+        pause();
+}
\ No newline at end of file
diff --git a/System2/create_ps/main.c b/System2/create_ps/main.c
index cd8879a..e553bea 100644
--- a/System2/create_ps/main.c
+++ b/System2/create_ps/main.c
@@ -5,8 +5,7 @@
 
 int main()
 {
-  pid_t fpid;
-
+  pid_t fpid; // fpid表示fork函数返回的值
   fpid = fork();
   // create child process
   if (fpid == -1)
diff --git a/System2/example_alarm/main.c b/System2/example_alarm/main.c
new file mode 100644
index 0000000..43e1e88
--- /dev/null
+++ b/System2/example_alarm/main.c
@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <signal.h>
+#include <unistd.h>
+
+void sig_handler(int signo)
+{
+    printf("in handler\n");
+}
+
+int main()
+{
+    signal(SIGALRM, sig_handler);
+    alarm(5);
+    for (size_t i = 0; i < 30; i++)
+    {
+
+        printf("i = %d, In main\n", i);
+        sleep(1);
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/System2/sendToFile/main.c b/System2/sendToFile/main.c
new file mode 100644
index 0000000..7b4502f
--- /dev/null
+++ b/System2/sendToFile/main.c
@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <signal.h>
+#include <unistd.h>
+
+void handler(int signum)
+{
+    FILE *fp;
+    fp = fopen("test.txt", "w");
+    fprintf(fp, "coucou, je suis bien en vie!\n");
+    fclose(fp);
+}
+
+int main()
+{
+    signal(SIGUSR1, handler);
+    for (size_t i = 0; i < 30; i++)
+    {
+
+        printf("i = %d, In main\n", i);
+        sleep(1);
+    }
+    return 0;
+}
diff --git a/System2/sendToFile/test.txt b/System2/sendToFile/test.txt
new file mode 100644
index 0000000..e69de29
diff --git a/TP3/List/main.c b/TP3/List/main.c
index 7a52834..23e9c34 100644
--- a/TP3/List/main.c
+++ b/TP3/List/main.c
@@ -10,7 +10,6 @@ int main()
 	SCell *cell;
 
 	list = CreateList();
-
 	printf("Add 5, 3, 1\n");
 	AddElementBegin(list, 5);
 	cell = AddElementBegin(list, 3);