diff options
Diffstat (limited to 'm4/ungetc.m4')
| -rw-r--r-- | m4/ungetc.m4 | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/m4/ungetc.m4 b/m4/ungetc.m4 new file mode 100644 index 00000000..749f6bd5 --- /dev/null +++ b/m4/ungetc.m4 @@ -0,0 +1,36 @@ +# ungetc.m4 serial 2 +dnl Copyright (C) 2009-2011 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +AC_DEFUN_ONCE([gl_FUNC_UNGETC_WORKS], +[ + AC_REQUIRE([AC_PROG_CC]) + + AC_CACHE_CHECK([whether ungetc works on arbitrary bytes], + [gl_cv_func_ungetc_works], + [AC_RUN_IFELSE([AC_LANG_PROGRAM([[ +#include <stdio.h> + ]], [FILE *f; + if (!(f = fopen ("conftest.tmp", "w+"))) return 1; + if (fputs ("abc", f) < 0) return 2; + rewind (f); + if (fgetc (f) != 'a') return 3; + if (fgetc (f) != 'b') return 4; + if (ungetc ('d', f) != 'd') return 5; + if (ftell (f) != 1) return 6; + if (fgetc (f) != 'd') return 7; + if (ftell (f) != 2) return 8; + if (fseek (f, 0, SEEK_CUR) != 0) return 9; + if (ftell (f) != 2) return 10; + if (fgetc (f) != 'c') return 11; + fclose (f); remove ("conftest.tmp");])], + [gl_cv_func_ungetc_works=yes], [gl_cv_func_ungetc_works=no], + [gl_cv_func_ungetc_works='guessing no']) + ]) + if test "$gl_cv_func_ungetc_works" != yes; then + AC_DEFINE([FUNC_UNGETC_BROKEN], [1], + [Define to 1 if ungetc is broken when used on arbitrary bytes.]) + fi +]) |