3 # Copyright (C) 2000, 2001, 2004 Free Software Foundation, Inc.
4 # This file is free software; the Free Software Foundation
5 # gives unlimited permission to copy and/or distribute it,
6 # with or without modifications, as long as this notice is preserved.
9 dnl Using code from emacs, based on suggestions from Paul Eggert
10 dnl and Ulrich Drepper.
12 dnl Find out how to determine the number of pending output bytes on a stream.
13 dnl glibc (2.1.93 and newer) and Solaris provide __fpending. On other systems,
14 dnl we have to grub around in the FILE struct.
16 AC_DEFUN([gl_FUNC_FPENDING],
18 AC_CHECK_HEADERS(stdio_ext.h)
19 AC_REPLACE_FUNCS([__fpending])
22 # include <stdio_ext.h>
25 AC_CHECK_DECLS([__fpending], , , $fp_headers)
26 if test $ac_cv_func___fpending = no; then
28 [how to determine the number of pending output bytes on a stream],
29 ac_cv_sys_pending_output_n_bytes,
34 'fp->_IO_write_ptr - fp->_IO_write_base' \
36 '# traditional Unix' \
37 'fp->_ptr - fp->_base' \
40 'fp->_p - fp->_bf._base' \
43 'fp->__ptr - fp->__base' \
46 'fp->__bufp - fp->__buffer' \
48 '# old glibc iostream?' \
49 'fp->_pptr - fp->_pbase' \
52 '(*fp)->_ptr - (*fp)->_base' \
54 '# e.g., DGUX R4.11; the info is not available' \
58 # Skip each embedded comment.
59 case "$ac_expr" in '#'*) continue;; esac
64 [FILE *fp = stdin; (void) ($ac_expr);],
67 test "$fp_done" = yes && break
70 ac_cv_sys_pending_output_n_bytes=$ac_expr
73 AC_DEFINE_UNQUOTED(PENDING_OUTPUT_N_BYTES,
74 $ac_cv_sys_pending_output_n_bytes,
75 [the number of pending output bytes on stream `fp'])