re PR libfortran/30162 (Document when sequential I/O with named pipes works)

2012-12-21  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR libfortran/30162
	* io/unix.c (raw_tell):  If the lseek is done on a
	non-seekable file, return 0.

From-SVN: r194679

libgfortran/ChangeLog

+2012-12-21  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	PR libfortran/30162
+	* io/unix.c (raw_tell):  If the lseek is done on a
+	non-seekable file, return 0.
+
 2012-12-20  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/36044

libgfortran/io/unix.c

@@ -344,7 +344,15 @@ raw_seek (unix_stream * s, gfc_offset offset, int whence)
 static gfc_offset
 raw_tell (unix_stream * s)
 {
-  return lseek (s->fd, 0, SEEK_CUR);
+  gfc_offset x;
+  x = lseek (s->fd, 0, SEEK_CUR);
+
+  /* Non-seekable files should always be assumed to be at
+     current position.  */
+  if (x == -1 && errno == ESPIPE)
+    x = 0;
+
+  return x;
 }
 
 static gfc_offset