diff options
Diffstat (limited to 'm4/fpending.m4')
| -rw-r--r-- | m4/fpending.m4 | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/m4/fpending.m4 b/m4/fpending.m4 new file mode 100644 index 0000000..c8d9e8b --- /dev/null +++ b/m4/fpending.m4 @@ -0,0 +1,95 @@ +# serial 20 + +# Copyright (C) 2000-2001, 2004-2013 Free Software Foundation, Inc. +# This file is free software; the Free Software Foundation +# gives unlimited permission to copy and/or distribute it, +# with or without modifications, as long as this notice is preserved. + +dnl From Jim Meyering +dnl Using code from emacs, based on suggestions from Paul Eggert +dnl and Ulrich Drepper. + +dnl Find out how to determine the number of pending output bytes on a stream. +dnl glibc (2.1.93 and newer) and Solaris provide __fpending. On other systems, +dnl we have to grub around in the FILE struct. + +AC_DEFUN([gl_FUNC_FPENDING], +[ + AC_CHECK_HEADERS_ONCE([stdio_ext.h]) + AC_CACHE_CHECK([for __fpending], [gl_cv_func___fpending], + [ + AC_LINK_IFELSE( + [AC_LANG_PROGRAM( + [[#include <stdio.h> + #if HAVE_STDIO_EXT_H + # include <stdio_ext.h> + #endif + ]], + [[return ! __fpending (stdin);]])], + [gl_cv_func___fpending=yes], + [gl_cv_func___fpending=no]) + ]) +]) + +AC_DEFUN([gl_PREREQ_FPENDING], +[ + AC_CACHE_CHECK( + [how to determine the number of pending output bytes on a stream], + ac_cv_sys_pending_output_n_bytes, + [ + for ac_expr in \ + \ + '# glibc2' \ + 'fp->_IO_write_ptr - fp->_IO_write_base' \ + \ + '# traditional Unix' \ + 'fp->_ptr - fp->_base' \ + \ + '# BSD' \ + 'fp->_p - fp->_bf._base' \ + \ + '# SCO, Unixware' \ + '(fp->__ptr ? fp->__ptr - fp->__base : 0)' \ + \ + '# QNX' \ + '(fp->_Mode & 0x2000 /*_MWRITE*/ ? fp->_Next - fp->_Buf : 0)' \ + \ + '# old glibc?' \ + 'fp->__bufp - fp->__buffer' \ + \ + '# old glibc iostream?' \ + 'fp->_pptr - fp->_pbase' \ + \ + '# emx+gcc' \ + 'fp->_ptr - fp->_buffer' \ + \ + '# Minix' \ + 'fp->_ptr - fp->_buf' \ + \ + '# Plan9' \ + 'fp->wp - fp->buf' \ + \ + '# VMS' \ + '(*fp)->_ptr - (*fp)->_base' \ + \ + '# e.g., DGUX R4.11; the info is not available' \ + 1 \ + ; do + + # Skip each embedded comment. + case "$ac_expr" in '#'*) continue;; esac + + AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>]], + [[FILE *fp = stdin; (void) ($ac_expr);]])], + [fp_done=yes] + ) + test "$fp_done" = yes && break + done + + ac_cv_sys_pending_output_n_bytes=$ac_expr + ] + ) + AC_DEFINE_UNQUOTED([PENDING_OUTPUT_N_BYTES], + $ac_cv_sys_pending_output_n_bytes, + [the number of pending output bytes on stream 'fp']) +]) |