+
+/****************************************************************************
+Set a fd into nonblocking mode
+****************************************************************************/
+void set_nonblocking(int fd)
+{
+ int val;
+
+ if((val = fcntl(fd, F_GETFL, 0)) == -1)
+ return;
+ if (!(val & NONBLOCK_FLAG)) {
+ val |= NONBLOCK_FLAG;
+ fcntl(fd, F_SETFL, val);
+ }
+}
+
+/****************************************************************************
+Set a fd into blocking mode
+****************************************************************************/
+void set_blocking(int fd)
+{
+ int val;
+
+ if((val = fcntl(fd, F_GETFL, 0)) == -1)
+ return;
+ if (val & NONBLOCK_FLAG) {
+ val &= ~NONBLOCK_FLAG;
+ fcntl(fd, F_SETFL, val);
+ }
+}
+
+
+/* create a file descriptor pair - like pipe() but use socketpair if
+ possible (because of blocking issues on pipes)
+
+ always set non-blocking
+ */
+int fd_pair(int fd[2])
+{
+ int ret;
+
+#if HAVE_SOCKETPAIR
+ ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fd);
+#else
+ ret = pipe(fd);
+#endif
+
+ if (ret == 0) {
+ set_nonblocking(fd[0]);
+ set_nonblocking(fd[1]);
+ }
+
+ return ret;
+}
+
+
+/* this is derived from CVS code */