1# serial 23 2 3# Copyright (C) 2000-2001, 2004-2021 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 (possibly opaque) FILE struct. 15 16AC_DEFUN([gl_FUNC_FPENDING], 17[ 18 AC_CHECK_HEADERS_ONCE([stdio_ext.h]) 19 fp_headers=' 20 #include <stdio.h> 21 #if HAVE_STDIO_EXT_H 22 # include <stdio_ext.h> 23 #endif 24 ' 25 AC_CACHE_CHECK([for __fpending], [gl_cv_func___fpending], 26 [ 27 AC_LINK_IFELSE( 28 [AC_LANG_PROGRAM([[$fp_headers]], 29 [[return ! __fpending (stdin);]])], 30 [gl_cv_func___fpending=yes], 31 [gl_cv_func___fpending=no]) 32 ]) 33 if test $gl_cv_func___fpending = yes; then 34 AC_CHECK_DECLS([__fpending], [], [], [$fp_headers]) 35 fi 36]) 37