diff --git a/src/iperf_server_api.c b/src/iperf_server_api.c
index 075c7dc..f76a2a8 100644
--- a/src/iperf_server_api.c
+++ b/src/iperf_server_api.c
@@ -110,7 +110,7 @@ int
 iperf_accept(struct iperf_test *test)
 {
     int s;
-    int rbuf = ACCESS_DENIED;
+    signed char rbuf = ACCESS_DENIED;
     char cookie[COOKIE_SIZE];
     socklen_t len;
     struct sockaddr_storage addr;
@@ -148,7 +148,7 @@ iperf_accept(struct iperf_test *test)
             i_errno = IERECVCOOKIE;
             return -1;
         }
-        if (Nwrite(s, (char*) &rbuf, sizeof(int), Ptcp) < 0) {
+        if (Nwrite(s, (char*) &rbuf, sizeof(rbuf), Ptcp) < 0) {
             i_errno = IESENDMESSAGE;
             return -1;
         }
diff --git a/src/iperf_tcp.c b/src/iperf_tcp.c
index 1bbc248..e80b53e 100644
--- a/src/iperf_tcp.c
+++ b/src/iperf_tcp.c
@@ -96,7 +96,7 @@ iperf_tcp_accept(struct iperf_test * test)
     }
 
     if (strcmp(test->cookie, cookie) != 0) {
-        if (Nwrite(s, (char*) &rbuf, sizeof(signed char), Ptcp) < 0) {
+        if (Nwrite(s, (char*) &rbuf, sizeof(rbuf), Ptcp) < 0) {
             i_errno = IESENDMESSAGE;
             return -1;
         }
diff --git a/src/iperf_util.c b/src/iperf_util.c
index 5393c5f..1b25dd6 100644
--- a/src/iperf_util.c
+++ b/src/iperf_util.c
@@ -136,7 +136,7 @@ delay(int64_t ns)
 
     while (nanosleep(&req, &rem) == -1)
         if (EINTR == errno)
-            memcpy(&req, &rem, sizeof rem);
+            memcpy(&req, &rem, sizeof(rem));
         else
             return -1;
     return 0;
diff --git a/src/tcp_window_size.c b/src/tcp_window_size.c
index 279c178..59819d0 100644
--- a/src/tcp_window_size.c
+++ b/src/tcp_window_size.c
@@ -90,7 +90,7 @@ set_tcp_windowsize(int sock, int bufsize, int dir)
          */
 //        printf("Setting TCP buffer to size: %d\n", bufsize);
 	newbufsize = bufsize;
-	rc = setsockopt(sock, SOL_SOCKET, dir, (char *) &newbufsize, sizeof newbufsize);
+	rc = setsockopt(sock, SOL_SOCKET, dir, (char *) &newbufsize, sizeof(newbufsize));
 	if (rc < 0)
 	    return rc;
     } else {