done till multi2.c

select_poll/multi1.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <fcntl.h>
+
+int main(){
+    int fd1, fd2;
+    char buf[10];
+    int n;
+    fd1 = open("./pone", O_RDWR);
+    fd2 = open("./ptwo", O_RDWR);
+
+    printf(" Trying to read from pone \n");
+    n = read( fd1, buf, 10);
+
+    printf(" read data = %s from pone \n", buf);
+    printf(" Trying to read from ptwo\n");
+    n = read( fd2, buf, 10);
+
+    printf(" read data = %s from ptwo \n", buf);
+    return 0;
+}

select_poll/multi2.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <fcntl.h>
+#include <stdlib.h>
+
+int main(){
+
+    int fd1, fd2;
+    fd_set read_set, write_set;
+    char buf[10];
+    struct timeval timeout;
+    int n;
+
+    timeout.tv_sec = 10;
+    fd1 = open("./pone", O_RDWR);
+    fd2 = open("./ptwo", O_RDWR);
+
+    FD_ZERO(&read_set);
+    FD_SET(fd1, &read_set);
+    FD_SET(fd2, &read_set);
+
+    n = select(FD_SETSIZE, &read_set, NULL, NULL, &timeout);
+    if( n < 0 ){
+        perror("select ");
+        exit(1);
+    }
+
+    // test whether fd1 is ready or not
+    if( FD_ISSET(fd1, &read_set) ){
+        printf(" reading from fd1 (pone)\n");
+        n = read(fd1, buf, 10);
+        printf(" read data = %s from pone \n", buf);
+    }
+
+    // test whether fd2 is ready or not
+    if( FD_ISSET(fd2, &read_set) ){
+        printf(" reading from fd2 (ptwo)\n");
+        n = read(fd2, buf, 10);
+        printf(" read data = %s from ptwo \n", buf);
+    }
+    
+    return 0;
+
+}