1#serial 6 2 3# Copyright (C) 2000, 2001, 2004, 2005 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. 7 8dnl From Jim Meyering 9dnl Using code from emacs, based on suggestions from Paul Eggert 10dnl and Ulrich Drepper. 11 12dnl Find out how to determine the number of pending output bytes on a stream. 13dnl glibc (2.1.93 and newer) and Solaris provide __fpending. On other systems, 14dnl we have to grub around in the FILE struct. 15 16AC_DEFUN([gl_FUNC_FPENDING], 17[ 18 AC_LIBSOURCES([__fpending.c, __fpending.h]) 19 20 AC_CHECK_HEADERS(stdio_ext.h) 21 AC_REPLACE_FUNCS([__fpending]) 22 fp_headers=' 23# if HAVE_STDIO_EXT_H 24# include <stdio_ext.h> 25# endif 26' 27 AC_CHECK_DECLS([__fpending], , , $fp_headers) 28 if test $ac_cv_func___fpending = no; then 29 AC_CACHE_CHECK( 30 [how to determine the number of pending output bytes on a stream], 31 ac_cv_sys_pending_output_n_bytes, 32 [ 33 for ac_expr in \ 34 \ 35 '# glibc2' \ 36 'fp->_IO_write_ptr - fp->_IO_write_base' \ 37 \ 38 '# traditional Unix' \ 39 'fp->_ptr - fp->_base' \ 40 \ 41 '# BSD' \ 42 'fp->_p - fp->_bf._base' \ 43 \ 44 '# SCO, Unixware' \ 45 'fp->__ptr - fp->__base' \ 46 \ 47 '# old glibc?' \ 48 'fp->__bufp - fp->__buffer' \ 49 \ 50 '# old glibc iostream?' \ 51 'fp->_pptr - fp->_pbase' \ 52 \ 53 '# VMS' \ 54 '(*fp)->_ptr - (*fp)->_base' \ 55 \ 56 '# e.g., DGUX R4.11; the info is not available' \ 57 1 \ 58 ; do 59 60 # Skip each embedded comment. 61 case "$ac_expr" in '#'*) continue;; esac 62 63 AC_TRY_COMPILE( 64 [#include <stdio.h> 65 ], 66 [FILE *fp = stdin; (void) ($ac_expr);], 67 fp_done=yes 68 ) 69 test "$fp_done" = yes && break 70 done 71 72 ac_cv_sys_pending_output_n_bytes=$ac_expr 73 ] 74 ) 75 AC_DEFINE_UNQUOTED(PENDING_OUTPUT_N_BYTES, 76 $ac_cv_sys_pending_output_n_bytes, 77 [the number of pending output bytes on stream `fp']) 78 fi 79]) 80