diff --git a/fdstream.cpp b/fdstream.cpp
index ae1c30b..a12b7b4 100644
--- a/fdstream.cpp
+++ b/fdstream.cpp
@@ -16,6 +16,7 @@ sc::io::fdostream::~fdostream() {
 void sc::io::fdostream::close() {
 	if (_outbuf.fd() != -1) {
 		::close(_outbuf.fd());
+		_outbuf.fd(-1);
 	}
 }
 
@@ -26,6 +27,7 @@ sc::io::fdistream::~fdistream() {
 void sc::io::fdistream::close() {
 	if (_inbuf.fd() != -1) {
 		::close(_inbuf.fd());
+		_inbuf.fd(-1);
 	}
 }
 
@@ -36,5 +38,6 @@ sc::io::fdstream::~fdstream() {
 void sc::io::fdstream::close() {
 	if (_iobuf.fd() != -1) {
 		::close(_iobuf.fd());
+		_iobuf.fd(-1);
 	}
 }