test: specify timeout as 0 to select when expecting nonblocking

Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>

Author: ktock

test/sockets/test_sockets_echo_client.c

@@ -67,13 +67,16 @@ void main_loop() {
   fd_set fdr;
   fd_set fdw;
   int res;
+  struct timeval tv;
 
   // make sure that server.fd is ready to read / write
   FD_ZERO(&fdr);
   FD_ZERO(&fdw);
   FD_SET(server.fd, &fdr);
   FD_SET(server.fd, &fdw);
-  res = select(64, &fdr, &fdw, NULL, NULL);
+  tv.tv_sec = 0;
+  tv.tv_usec = 0;
+  res = select(64, &fdr, &fdw, NULL, &tv);
   if (res == -1) {
     perror("select failed");
     finish(EXIT_FAILURE);

test/sockets/test_sockets_echo_server.c

@@ -77,6 +77,7 @@ void main_loop() {
   int res;
   fd_set fdr;
   fd_set fdw;
+  struct timeval tv;
 
   // see if there are any connections to accept or read / write from
   FD_ZERO(&fdr);
@@ -87,7 +88,9 @@ void main_loop() {
   if (client.fd) FD_SET(client.fd, &fdr);
   if (client.fd) FD_SET(client.fd, &fdw);
 #endif
-  res = select(64, &fdr, &fdw, NULL, NULL);
+  tv.tv_sec = 0;
+  tv.tv_usec = 0;
+  res = select(64, &fdr, &fdw, NULL, &tv);
   if (res == -1) {
     perror("select failed");
     exit(EXIT_SUCCESS);