diff --git a/common/os_calls.c b/common/os_calls.c
index cfbd7cd8..bb352a4d 100644
--- a/common/os_calls.c
+++ b/common/os_calls.c
@@ -1408,7 +1408,7 @@ g_sck_last_error_would_block(int sck)
 
 /*****************************************************************************/
 int
-g_sck_recv(int sck, void *ptr, int len, int flags)
+g_sck_recv(int sck, void *ptr, unsigned int len, int flags)
 {
 #if defined(_WIN32)
     return recv(sck, (char *)ptr, len, flags);
@@ -1419,7 +1419,7 @@ g_sck_recv(int sck, void *ptr, int len, int flags)
 
 /*****************************************************************************/
 int
-g_sck_send(int sck, const void *ptr, int len, int flags)
+g_sck_send(int sck, const void *ptr, unsigned int len, int flags)
 {
 #if defined(_WIN32)
     return send(sck, (const char *)ptr, len, flags);
diff --git a/common/os_calls.h b/common/os_calls.h
index c7dc1b67..f01bd6fc 100644
--- a/common/os_calls.h
+++ b/common/os_calls.h
@@ -86,8 +86,8 @@ int      g_sck_vsock_bind_address(int sck, const char *port, const char *address
 int      g_tcp_bind_address(int sck, const char *port, const char *address);
 int      g_sck_listen(int sck);
 int      g_sck_accept(int sck);
-int      g_sck_recv(int sck, void *ptr, int len, int flags);
-int      g_sck_send(int sck, const void *ptr, int len, int flags);
+int      g_sck_recv(int sck, void *ptr, unsigned int len, int flags);
+int      g_sck_send(int sck, const void *ptr, unsigned int len, int flags);
 int      g_sck_last_error_would_block(int sck);
 int      g_sck_socket_ok(int sck);
 int      g_sck_can_send(int sck, int millis);