Use send() with MSG_DONTWAIT when possible
diff --git a/common/rdr/FdOutStream.cxx b/common/rdr/FdOutStream.cxx
index 29e864f..32245a6 100644
--- a/common/rdr/FdOutStream.cxx
+++ b/common/rdr/FdOutStream.cxx
@@ -34,6 +34,7 @@
#include <sys/types.h>
#include <unistd.h>
#include <sys/time.h>
+#include <sys/socket.h>
#endif
/* Old systems have select() in sys/time.h */
@@ -193,7 +194,14 @@
return 0;
do {
- n = ::write(fd, data, length);
+ // select only guarantees that you can write SO_SNDLOWAT without
+ // blocking, which is normally 1. Use MSG_DONTWAIT to avoid
+ // blocking, when possible.
+#ifndef MSG_DONTWAIT
+ n = ::send(fd, (const char*)data, length, 0);
+#else
+ n = ::send(fd, (const char*)data, length, MSG_DONTWAIT);
+#endif
} while (n < 0 && (errno == EINTR));
if (n < 0)