feat: exec() 函数族：execl() / execlp()

unix_linux_09_exec/hello.cpp

@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <unistd.h>
+
+int main(int argc, char *argv[])
+{
+    while (true) {
+        sleep(1);
+        printf("hello world\n");
+    }
+    
+    return 0;
+}

unix_linux_09_exec/myexec.cpp

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <unistd.h>
+
+int main(int argc, char *argv[])
+{
+    for (int i = 0; i < 3; i++)
+        printf("-----i = %d\n", i);
+
+    pid_t pid = fork();  //创建子进程
+
+    if (pid == 0) {
+        execl("/bin/ls", "占位参数", "-al", NULL);  //ls 程序使用子进程的地址空间
+//        execl("./hello", "占位参数", NULL);           //一般是调用自己的程序，而非系统的程序
+    }
+
+    for (int i = 0; i < 3; i++)
+        printf("+++++i = %d\n", i);
+
+    return 0;
+}