Index: uspace/libc/generic/io/stream.c
===================================================================
--- uspace/libc/generic/io/stream.c	(revision d681c173694bd83b842b2932968cec935ec1f26f)
+++ uspace/libc/generic/io/stream.c	(revision 253f35a1d714bef0e93e4a79768b7342ccc84123)
@@ -165,7 +165,5 @@
 ssize_t write(int fd, const void *buf, size_t count)
 {
-//	__SYSCALL3(SYS_IO, 1, (sysarg_t)buf, (sysarg_t) count);
-//	return count;
-	if (fd < FDS)
+	if (fd < FDS && streams[fd].w)
 		return streams[fd].w(streams[fd].param, buf, count);
 	
@@ -175,5 +173,5 @@
 ssize_t read(int fd, void *buf, size_t count)
 {
-	if (fd < FDS)
+	if (fd < FDS && streams[fd].r)
 		return streams[fd].r(streams[fd].param, buf, count);