pipes can be blocking, non blocking or blocking on one side only

default is again blocking, because it causes less trouble

mrw/unistd.hpp

@@ -9,6 +9,10 @@
     @license LGPL, see file <a href="license.html">COPYING</a>
 
     $Log$
+    Revision 1.7  2004/12/18 20:58:19  marc
+    pipes can be blocking, non blocking or blocking on one side only
+    default is again blocking, because it causes less trouble
+
     Revision 1.6  2004/12/14 20:32:10  marc
     support for connect_cin
     pipe is now non blocking by default
@@ -55,20 +59,30 @@ namespace mrw {
     int _fd[2];
     int _lastError;
   public:
+    /// blocking mode
+    enum BlockingMode {
+      non_blocking,             ///< both sides are non blocking
+      block_input,              ///< pipe input is blocking
+      block_output,             ///< pipe output is blocking
+      blocking                  ///< both sides are blocking
+    };
     /// creates a unix pipe
-    /** @param blocking Flag whether the pipe is blocking (default: no) */
-    Pipe(bool blocking=false) throw(std::bad_exception): _lastError(-1) {
+    /** @param mode Flag whether the pipe is blocking (default: yes) */
+    Pipe(BlockingMode mode=blocking) throw(std::bad_exception):
+      _lastError(-1) {
       _fd[0] = -1;
       _fd[1] = -1;
       if (::pipe(_fd)==-1) {
         _lastError=errno;
         return;
       }
-      if (!blocking) {
+      if (mode==non_blocking || mode==block_output) {
         int val(fcntl(_fd[0], F_GETFL, 0));
         if (fcntl(_fd[0], F_SETFL, (val!=-1?val:0)|O_NONBLOCK) == -1)
           _lastError=errno;
-        val = fcntl(_fd[1], F_GETFL, 0);
+      }
+      if (mode==non_blocking || mode==block_input) {
+        int val(fcntl(_fd[1], F_GETFL, 0));
         if (fcntl(_fd[1], F_SETFL, (val!=-1?val:0)|O_NONBLOCK) == -1)
           _lastError=errno;
       }