- simplify descriptions of stream positioning in various open modes

- mention that append mode always forces the stream position to EOF
  on writes

from NetBSD -r 1.9

ok millert, jmc

1 files changed, 15 insertions, 8 deletions

diff --git a/lib/libc/stdio/fopen.3 b/lib/libc/stdio/fopen.3
index 8c6a3902413..7d260aaded1 100644
--- a/lib/libc/stdio/fopen.3
+++ b/lib/libc/stdio/fopen.3
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: fopen.3,v 1.16 2003/06/02 20:18:37 millert Exp $
+.\"	$OpenBSD: fopen.3,v 1.17 2005/07/26 03:06:09 jaredy Exp $
 .\"
 .\" Copyright (c) 1990, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -60,26 +60,20 @@ points to a string beginning with one of the following
 sequences (additional characters may follow these sequences):
 .Bl -tag -width indent
 .It Dq Li r
-Open text file for reading.
-The stream is positioned at the beginning of the file.
+Open file for reading.
 .It Dq Li r+
 Open for reading and writing.
-The stream is positioned at the beginning of the file.
 .It Dq Li w
 Truncate file to zero length or create text file for writing.
-The stream is positioned at the beginning of the file.
 .It Dq Li w+
 Open for reading and writing.
 The file is created if it does not exist, otherwise it is truncated.
-The stream is positioned at the beginning of the file.
 .It Dq Li a
 Open for writing.
 The file is created if it does not exist.
-The stream is positioned at the end of the file.
 .It Dq Li a+
 Open for reading and writing.
 The file is created if it does not exist.
-The stream is positioned at the end of the file.
 .El
 .Pp
 The
@@ -91,6 +85,18 @@ This is strictly for compatibility with
 .St -ansiC
 and has no effect; the ``b'' is ignored.
 .Pp
+The
+.Fn fopen
+and
+.Fn freopen
+functions initially position the stream at the start of the file
+unless the file is opened in append mode,
+in which case the stream is initially positioned at the end of the file.
+.Pp
+Opening a file in append mode causes all subsequent writes to it
+to be forced to the current end-of-file, regardless of intervening
+repositioning of the stream.
+.Pp
 Any created files will have mode
 .Pf \\*q Dv S_IRUSR
 \&|
@@ -121,6 +127,7 @@ function associates a stream with the existing file descriptor
 The
 .Fa mode
 of the stream must be compatible with the mode of the file descriptor.
+The stream is positioned at the file offset of the file descriptor.
 If
 .Fn fdopen
 fails, the file descriptor