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Diffstat (limited to 'm4/stpncpy.m4')
| -rw-r--r-- | m4/stpncpy.m4 | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/m4/stpncpy.m4 b/m4/stpncpy.m4 new file mode 100644 index 0000000..928a38a --- /dev/null +++ b/m4/stpncpy.m4 @@ -0,0 +1,105 @@ +# stpncpy.m4 serial 18 +dnl Copyright (C) 2002-2003, 2005-2007, 2009-2020 Free Software Foundation, +dnl 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([gl_FUNC_STPNCPY], +[ + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + + dnl Persuade glibc <string.h> to declare stpncpy(). + AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) + + dnl The stpncpy() declaration in lib/string.in.h uses 'restrict'. + AC_REQUIRE([AC_C_RESTRICT]) + + AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS]) + + dnl Both glibc and AIX (4.3.3, 5.1) have an stpncpy() function + dnl declared in <string.h>. Its side effects are the same as those + dnl of strncpy(): + dnl stpncpy (dest, src, n) + dnl overwrites dest[0..n-1], min(strlen(src),n) bytes coming from src, + dnl and the remaining bytes being NULs. However, the return value is + dnl in glibc: dest + min(strlen(src),n) + dnl in AIX: dest + max(0,n-1) + dnl Only the glibc return value is useful in practice. + + AC_CHECK_DECLS_ONCE([stpncpy]) + AC_CHECK_FUNCS_ONCE([stpncpy]) + if test $ac_cv_func_stpncpy = yes; then + AC_CACHE_CHECK([for working stpncpy], [gl_cv_func_stpncpy], [ + AC_RUN_IFELSE( + [AC_LANG_SOURCE([[ +#include <stdlib.h> +#include <string.h> /* for strcpy */ +/* The stpncpy prototype is missing in <string.h> on AIX 4. */ +#if !HAVE_DECL_STPNCPY +extern +# ifdef __cplusplus +"C" +# endif +char *stpncpy (char *dest, const char *src, size_t n); +#endif +int main () +{ + int result = 0; + const char *src = "Hello"; + char dest[10]; + /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+1 here. */ + { + strcpy (dest, "\377\377\377\377\377\377"); + if (stpncpy (dest, src, 2) != dest + 2) + result |= 1; + } + /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+4 here. */ + { + strcpy (dest, "\377\377\377\377\377\377"); + if (stpncpy (dest, src, 5) != dest + 5) + result |= 2; + } + /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+6 here. */ + { + strcpy (dest, "\377\377\377\377\377\377"); + if (stpncpy (dest, src, 7) != dest + 5) + result |= 4; + } + return result; +} +]])], + [gl_cv_func_stpncpy=yes], + [gl_cv_func_stpncpy=no], + [dnl Guess yes on glibc systems and musl systems. + AC_EGREP_CPP([Thanks for using GNU], [ +#include <features.h> +#ifdef __GNU_LIBRARY__ + Thanks for using GNU +#endif +], [gl_cv_func_stpncpy="guessing yes"], + [case "$host_os" in + *-musl*) gl_cv_func_stpncpy="guessing yes" ;; + *) gl_cv_func_stpncpy="$gl_cross_guess_normal" ;; + esac + ]) + ]) + ]) + case "$gl_cv_func_stpncpy" in + *yes) + AC_DEFINE([HAVE_STPNCPY], [1], + [Define if you have the stpncpy() function and it works.]) + ;; + *) + REPLACE_STPNCPY=1 + ;; + esac + else + HAVE_STPNCPY=0 + fi +]) + +# Prerequisites of lib/stpncpy.c. +AC_DEFUN([gl_PREREQ_STPNCPY], [ + : +]) |