nonblocking: Add comment.

* lib/fcntl.in.h (O_NONBLOCK): Add comment.

diff --git a/ChangeLog b/ChangeLog
index d0923da0e919c418345a95bdefcd229a40172c98..1f09ff84580f69088eb2a3222313b86dd76d845b 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2011-04-17  Bruno Haible  <bruno@clisp.org>
+
+       nonblocking: Add comment.
+       * lib/fcntl.in.h (O_NONBLOCK): Add comment.
+
 2011-04-17  Bruno Haible  <bruno@clisp.org>
 
        nonblocking: Add tests for sockets.

diff --git a/lib/fcntl.in.h b/lib/fcntl.in.h
index 971316fc05d07c720c0310803d7509f7c7b952b9..ce7c8c016cb29f26d157aaff7402d276b929efe3 100644 (file)
--- a/lib/fcntl.in.h
+++ b/lib/fcntl.in.h
@@ -218,6 +218,9 @@ _GL_WARN_ON_USE (openat, "openat is not portable - "
 # define O_NONBLOCK O_NDELAY
 #endif
 
+/* If the gnulib module 'nonblocking' is in use, guarantee a working non-zero
+   value of O_NONBLOCK.  Otherwise, O_NONBLOCK is defined (above) to O_NDELAY
+   or to 0 as fallback.  */
 #if @GNULIB_NONBLOCKING@
 # if O_NONBLOCK
 #  define GNULIB_defined_O_NONBLOCK 0