Mercurial > gnulib
changeset 13199:af2bd6fe2a98
vasnprintf: Correct handling of unconvertible wide string arguments.
| author | Bruno Haible <bruno@clisp.org> |
|---|---|
| date | Sat, 10 Apr 2010 22:25:31 +0200 |
| parents | 2f3ddf3c58a5 |
| children | 69f672943274 |
| files | ChangeLog lib/vasnprintf.c m4/vasnprintf.m4 modules/vasnprintf |
| diffstat | 4 files changed, 332 insertions(+), 255 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog Sat Apr 10 22:17:02 2010 +0200 +++ b/ChangeLog Sat Apr 10 22:25:31 2010 +0200 @@ -1,3 +1,18 @@ +2010-04-10 Bruno Haible <bruno@clisp.org> + + vasnprintf: Correct handling of unconvertible wide string arguments. + * lib/vasnprintf.c (MAX_ROOM_NEEDED): New function, extracted from + VASNPRINTF. + (VASNPRINTF): Use it. After snprintf failed, allocate more memory only + if HAVE_SNPRINTF_RETVAL_C99 is false and the allocated memory is + smaller than the expected maximum need for the directive. Set errno to + EILSEQ, not EINVAL, when the directive is 'c' or 's'. + (local_strnlen, local_wcslen, local_wcsnlen): Update conditions. + * m4/vasnprintf.m4 (gl_PREREQ_VASNPRINTF): Require AC_C_INLINE and + gl_SNPRINTF_RETVAL_C99. Define HAVE_SNPRINTF_RETVAL_C99. + * modules/vasnprintf (Files): Add m4/printf.m4. + Reported by Jarno Rajahalme <jarno.rajahalme@nsn.com>. + 2010-04-10 Bruno Haible <bruno@clisp.org> vasnprintf: Fix crash in %ls directive.
--- a/lib/vasnprintf.c Sat Apr 10 22:17:02 2010 +0200 +++ b/lib/vasnprintf.c Sat Apr 10 22:25:31 2010 +0200 @@ -207,7 +207,7 @@ #undef remainder #define remainder rem -#if !USE_SNPRINTF && !WIDE_CHAR_VERSION +#if (!USE_SNPRINTF || !HAVE_SNPRINTF_RETVAL_C99) && !WIDE_CHAR_VERSION # if (HAVE_STRNLEN && !defined _AIX) # define local_strnlen strnlen # else @@ -223,7 +223,7 @@ # endif #endif -#if (!USE_SNPRINTF || (NEED_PRINTF_DIRECTIVE_LS && !defined IN_LIBINTL)) && HAVE_WCHAR_T && (WIDE_CHAR_VERSION || DCHAR_IS_TCHAR) +#if (((!USE_SNPRINTF || !HAVE_SNPRINTF_RETVAL_C99) && WIDE_CHAR_VERSION) || ((!USE_SNPRINTF || !HAVE_SNPRINTF_RETVAL_C99 || (NEED_PRINTF_DIRECTIVE_LS && !defined IN_LIBINTL)) && !WIDE_CHAR_VERSION && DCHAR_IS_TCHAR)) && HAVE_WCHAR_T # if HAVE_WCSLEN # define local_wcslen wcslen # else @@ -246,7 +246,7 @@ # endif #endif -#if !USE_SNPRINTF && HAVE_WCHAR_T && WIDE_CHAR_VERSION +#if (!USE_SNPRINTF || !HAVE_SNPRINTF_RETVAL_C99) && HAVE_WCHAR_T && WIDE_CHAR_VERSION # if HAVE_WCSNLEN # define local_wcsnlen wcsnlen # else @@ -1487,6 +1487,258 @@ #endif +#if !USE_SNPRINTF || !HAVE_SNPRINTF_RETVAL_C99 + +/* Use a different function name, to make it possible that the 'wchar_t' + parametrization and the 'char' parametrization get compiled in the same + translation unit. */ +# if WIDE_CHAR_VERSION +# define MAX_ROOM_NEEDED wmax_room_needed +# else +# define MAX_ROOM_NEEDED max_room_needed +# endif + +/* Returns the number of TCHAR_T units needed as temporary space for the result + of sprintf or SNPRINTF of a single conversion directive. */ +static inline size_t +MAX_ROOM_NEEDED (const arguments *ap, size_t arg_index, FCHAR_T conversion, + arg_type type, int flags, size_t width, int has_precision, + size_t precision, int pad_ourselves) +{ + size_t tmp_length; + + switch (conversion) + { + case 'd': case 'i': case 'u': +# if HAVE_LONG_LONG_INT + if (type == TYPE_LONGLONGINT || type == TYPE_ULONGLONGINT) + tmp_length = + (unsigned int) (sizeof (unsigned long long) * CHAR_BIT + * 0.30103 /* binary -> decimal */ + ) + + 1; /* turn floor into ceil */ + else +# endif + if (type == TYPE_LONGINT || type == TYPE_ULONGINT) + tmp_length = + (unsigned int) (sizeof (unsigned long) * CHAR_BIT + * 0.30103 /* binary -> decimal */ + ) + + 1; /* turn floor into ceil */ + else + tmp_length = + (unsigned int) (sizeof (unsigned int) * CHAR_BIT + * 0.30103 /* binary -> decimal */ + ) + + 1; /* turn floor into ceil */ + if (tmp_length < precision) + tmp_length = precision; + /* Multiply by 2, as an estimate for FLAG_GROUP. */ + tmp_length = xsum (tmp_length, tmp_length); + /* Add 1, to account for a leading sign. */ + tmp_length = xsum (tmp_length, 1); + break; + + case 'o': +# if HAVE_LONG_LONG_INT + if (type == TYPE_LONGLONGINT || type == TYPE_ULONGLONGINT) + tmp_length = + (unsigned int) (sizeof (unsigned long long) * CHAR_BIT + * 0.333334 /* binary -> octal */ + ) + + 1; /* turn floor into ceil */ + else +# endif + if (type == TYPE_LONGINT || type == TYPE_ULONGINT) + tmp_length = + (unsigned int) (sizeof (unsigned long) * CHAR_BIT + * 0.333334 /* binary -> octal */ + ) + + 1; /* turn floor into ceil */ + else + tmp_length = + (unsigned int) (sizeof (unsigned int) * CHAR_BIT + * 0.333334 /* binary -> octal */ + ) + + 1; /* turn floor into ceil */ + if (tmp_length < precision) + tmp_length = precision; + /* Add 1, to account for a leading sign. */ + tmp_length = xsum (tmp_length, 1); + break; + + case 'x': case 'X': +# if HAVE_LONG_LONG_INT + if (type == TYPE_LONGLONGINT || type == TYPE_ULONGLONGINT) + tmp_length = + (unsigned int) (sizeof (unsigned long long) * CHAR_BIT + * 0.25 /* binary -> hexadecimal */ + ) + + 1; /* turn floor into ceil */ + else +# endif + if (type == TYPE_LONGINT || type == TYPE_ULONGINT) + tmp_length = + (unsigned int) (sizeof (unsigned long) * CHAR_BIT + * 0.25 /* binary -> hexadecimal */ + ) + + 1; /* turn floor into ceil */ + else + tmp_length = + (unsigned int) (sizeof (unsigned int) * CHAR_BIT + * 0.25 /* binary -> hexadecimal */ + ) + + 1; /* turn floor into ceil */ + if (tmp_length < precision) + tmp_length = precision; + /* Add 2, to account for a leading sign or alternate form. */ + tmp_length = xsum (tmp_length, 2); + break; + + case 'f': case 'F': + if (type == TYPE_LONGDOUBLE) + tmp_length = + (unsigned int) (LDBL_MAX_EXP + * 0.30103 /* binary -> decimal */ + * 2 /* estimate for FLAG_GROUP */ + ) + + 1 /* turn floor into ceil */ + + 10; /* sign, decimal point etc. */ + else + tmp_length = + (unsigned int) (DBL_MAX_EXP + * 0.30103 /* binary -> decimal */ + * 2 /* estimate for FLAG_GROUP */ + ) + + 1 /* turn floor into ceil */ + + 10; /* sign, decimal point etc. */ + tmp_length = xsum (tmp_length, precision); + break; + + case 'e': case 'E': case 'g': case 'G': + tmp_length = + 12; /* sign, decimal point, exponent etc. */ + tmp_length = xsum (tmp_length, precision); + break; + + case 'a': case 'A': + if (type == TYPE_LONGDOUBLE) + tmp_length = + (unsigned int) (LDBL_DIG + * 0.831 /* decimal -> hexadecimal */ + ) + + 1; /* turn floor into ceil */ + else + tmp_length = + (unsigned int) (DBL_DIG + * 0.831 /* decimal -> hexadecimal */ + ) + + 1; /* turn floor into ceil */ + if (tmp_length < precision) + tmp_length = precision; + /* Account for sign, decimal point etc. */ + tmp_length = xsum (tmp_length, 12); + break; + + case 'c': +# if HAVE_WINT_T && !WIDE_CHAR_VERSION + if (type == TYPE_WIDE_CHAR) + tmp_length = MB_CUR_MAX; + else +# endif + tmp_length = 1; + break; + + case 's': +# if HAVE_WCHAR_T + if (type == TYPE_WIDE_STRING) + { +# if WIDE_CHAR_VERSION + /* ISO C says about %ls in fwprintf: + "If the precision is not specified or is greater than the size + of the array, the array shall contain a null wide character." + So if there is a precision, we must not use wcslen. */ + const wchar_t *arg = ap->arg[arg_index].a.a_wide_string; + + if (has_precision) + tmp_length = local_wcsnlen (arg, precision); + else + tmp_length = local_wcslen (arg); +# else + /* ISO C says about %ls in fprintf: + "If a precision is specified, no more than that many bytes are + written (including shift sequences, if any), and the array + shall contain a null wide character if, to equal the multibyte + character sequence length given by the precision, the function + would need to access a wide character one past the end of the + array." + So if there is a precision, we must not use wcslen. */ + /* This case has already been handled separately in VASNPRINTF. */ + abort (); +# endif + } + else +# endif + { +# if WIDE_CHAR_VERSION + /* ISO C says about %s in fwprintf: + "If the precision is not specified or is greater than the size + of the converted array, the converted array shall contain a + null wide character." + So if there is a precision, we must not use strlen. */ + /* This case has already been handled separately in VASNPRINTF. */ + abort (); +# else + /* ISO C says about %s in fprintf: + "If the precision is not specified or greater than the size of + the array, the array shall contain a null character." + So if there is a precision, we must not use strlen. */ + const char *arg = ap->arg[arg_index].a.a_string; + + if (has_precision) + tmp_length = local_strnlen (arg, precision); + else + tmp_length = strlen (arg); +# endif + } + break; + + case 'p': + tmp_length = + (unsigned int) (sizeof (void *) * CHAR_BIT + * 0.25 /* binary -> hexadecimal */ + ) + + 1 /* turn floor into ceil */ + + 2; /* account for leading 0x */ + break; + + default: + abort (); + } + + if (!pad_ourselves) + { +# if ENABLE_UNISTDIO + /* Padding considers the number of characters, therefore the number of + elements after padding may be + > max (tmp_length, width) + but is certainly + <= tmp_length + width. */ + tmp_length = xsum (tmp_length, width); +# else + /* Padding considers the number of elements, says POSIX. */ + if (tmp_length < width) + tmp_length = width; +# endif + } + + tmp_length = xsum (tmp_length, 1); /* account for trailing NUL */ + + return tmp_length; +} + +#endif + DCHAR_T * VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp, const FCHAR_T *format, va_list args) @@ -2116,7 +2368,7 @@ } } #endif -#if (!USE_SNPRINTF || (NEED_PRINTF_DIRECTIVE_LS && !defined IN_LIBINTL)) && HAVE_WCHAR_T +#if (!USE_SNPRINTF || !HAVE_SNPRINTF_RETVAL_C99 || (NEED_PRINTF_DIRECTIVE_LS && !defined IN_LIBINTL)) && HAVE_WCHAR_T else if (dp->conversion == 's' # if WIDE_CHAR_VERSION && a.arg[dp->arg_index].type != TYPE_WIDE_STRING @@ -4322,11 +4574,11 @@ { arg_type type = a.arg[dp->arg_index].type; int flags = dp->flags; -#if !USE_SNPRINTF || !DCHAR_IS_TCHAR || ENABLE_UNISTDIO || NEED_PRINTF_FLAG_LEFTADJUST || NEED_PRINTF_FLAG_ZERO || NEED_PRINTF_UNBOUNDED_PRECISION +#if !USE_SNPRINTF || !HAVE_SNPRINTF_RETVAL_C99 || !DCHAR_IS_TCHAR || ENABLE_UNISTDIO || NEED_PRINTF_FLAG_LEFTADJUST || NEED_PRINTF_FLAG_ZERO || NEED_PRINTF_UNBOUNDED_PRECISION int has_width; size_t width; #endif -#if !USE_SNPRINTF || NEED_PRINTF_UNBOUNDED_PRECISION +#if !USE_SNPRINTF || !HAVE_SNPRINTF_RETVAL_C99 || NEED_PRINTF_UNBOUNDED_PRECISION int has_precision; size_t precision; #endif @@ -4351,7 +4603,7 @@ TCHAR_T *tmp; #endif -#if !USE_SNPRINTF || !DCHAR_IS_TCHAR || ENABLE_UNISTDIO || NEED_PRINTF_FLAG_LEFTADJUST || NEED_PRINTF_FLAG_ZERO || NEED_PRINTF_UNBOUNDED_PRECISION +#if !USE_SNPRINTF || !HAVE_SNPRINTF_RETVAL_C99 || !DCHAR_IS_TCHAR || ENABLE_UNISTDIO || NEED_PRINTF_FLAG_LEFTADJUST || NEED_PRINTF_FLAG_ZERO || NEED_PRINTF_UNBOUNDED_PRECISION has_width = 0; width = 0; if (dp->width_start != dp->width_end) @@ -4385,7 +4637,7 @@ } #endif -#if !USE_SNPRINTF || NEED_PRINTF_UNBOUNDED_PRECISION +#if !USE_SNPRINTF || !HAVE_SNPRINTF_RETVAL_C99 || NEED_PRINTF_UNBOUNDED_PRECISION has_precision = 0; precision = 6; if (dp->precision_start != dp->precision_end) @@ -4458,246 +4710,10 @@ #if !USE_SNPRINTF /* Allocate a temporary buffer of sufficient size for calling sprintf. */ - { - switch (dp->conversion) - { - - case 'd': case 'i': case 'u': -# if HAVE_LONG_LONG_INT - if (type == TYPE_LONGLONGINT || type == TYPE_ULONGLONGINT) - tmp_length = - (unsigned int) (sizeof (unsigned long long) * CHAR_BIT - * 0.30103 /* binary -> decimal */ - ) - + 1; /* turn floor into ceil */ - else -# endif - if (type == TYPE_LONGINT || type == TYPE_ULONGINT) - tmp_length = - (unsigned int) (sizeof (unsigned long) * CHAR_BIT - * 0.30103 /* binary -> decimal */ - ) - + 1; /* turn floor into ceil */ - else - tmp_length = - (unsigned int) (sizeof (unsigned int) * CHAR_BIT - * 0.30103 /* binary -> decimal */ - ) - + 1; /* turn floor into ceil */ - if (tmp_length < precision) - tmp_length = precision; - /* Multiply by 2, as an estimate for FLAG_GROUP. */ - tmp_length = xsum (tmp_length, tmp_length); - /* Add 1, to account for a leading sign. */ - tmp_length = xsum (tmp_length, 1); - break; - - case 'o': -# if HAVE_LONG_LONG_INT - if (type == TYPE_LONGLONGINT || type == TYPE_ULONGLONGINT) - tmp_length = - (unsigned int) (sizeof (unsigned long long) * CHAR_BIT - * 0.333334 /* binary -> octal */ - ) - + 1; /* turn floor into ceil */ - else -# endif - if (type == TYPE_LONGINT || type == TYPE_ULONGINT) - tmp_length = - (unsigned int) (sizeof (unsigned long) * CHAR_BIT - * 0.333334 /* binary -> octal */ - ) - + 1; /* turn floor into ceil */ - else - tmp_length = - (unsigned int) (sizeof (unsigned int) * CHAR_BIT - * 0.333334 /* binary -> octal */ - ) - + 1; /* turn floor into ceil */ - if (tmp_length < precision) - tmp_length = precision; - /* Add 1, to account for a leading sign. */ - tmp_length = xsum (tmp_length, 1); - break; - - case 'x': case 'X': -# if HAVE_LONG_LONG_INT - if (type == TYPE_LONGLONGINT || type == TYPE_ULONGLONGINT) - tmp_length = - (unsigned int) (sizeof (unsigned long long) * CHAR_BIT - * 0.25 /* binary -> hexadecimal */ - ) - + 1; /* turn floor into ceil */ - else -# endif - if (type == TYPE_LONGINT || type == TYPE_ULONGINT) - tmp_length = - (unsigned int) (sizeof (unsigned long) * CHAR_BIT - * 0.25 /* binary -> hexadecimal */ - ) - + 1; /* turn floor into ceil */ - else - tmp_length = - (unsigned int) (sizeof (unsigned int) * CHAR_BIT - * 0.25 /* binary -> hexadecimal */ - ) - + 1; /* turn floor into ceil */ - if (tmp_length < precision) - tmp_length = precision; - /* Add 2, to account for a leading sign or alternate form. */ - tmp_length = xsum (tmp_length, 2); - break; - - case 'f': case 'F': - if (type == TYPE_LONGDOUBLE) - tmp_length = - (unsigned int) (LDBL_MAX_EXP - * 0.30103 /* binary -> decimal */ - * 2 /* estimate for FLAG_GROUP */ - ) - + 1 /* turn floor into ceil */ - + 10; /* sign, decimal point etc. */ - else - tmp_length = - (unsigned int) (DBL_MAX_EXP - * 0.30103 /* binary -> decimal */ - * 2 /* estimate for FLAG_GROUP */ - ) - + 1 /* turn floor into ceil */ - + 10; /* sign, decimal point etc. */ - tmp_length = xsum (tmp_length, precision); - break; - - case 'e': case 'E': case 'g': case 'G': - tmp_length = - 12; /* sign, decimal point, exponent etc. */ - tmp_length = xsum (tmp_length, precision); - break; - - case 'a': case 'A': - if (type == TYPE_LONGDOUBLE) - tmp_length = - (unsigned int) (LDBL_DIG - * 0.831 /* decimal -> hexadecimal */ - ) - + 1; /* turn floor into ceil */ - else - tmp_length = - (unsigned int) (DBL_DIG - * 0.831 /* decimal -> hexadecimal */ - ) - + 1; /* turn floor into ceil */ - if (tmp_length < precision) - tmp_length = precision; - /* Account for sign, decimal point etc. */ - tmp_length = xsum (tmp_length, 12); - break; - - case 'c': -# if HAVE_WINT_T && !WIDE_CHAR_VERSION - if (type == TYPE_WIDE_CHAR) - tmp_length = MB_CUR_MAX; - else -# endif - tmp_length = 1; - break; - - case 's': -# if HAVE_WCHAR_T - if (type == TYPE_WIDE_STRING) - { -# if WIDE_CHAR_VERSION - /* ISO C says about %ls in fwprintf: - "If the precision is not specified or is greater - than the size of the array, the array shall - contain a null wide character." - So if there is a precision, we must not use - wcslen. */ - const wchar_t *arg = - a.arg[dp->arg_index].a.a_wide_string; - - if (has_precision) - tmp_length = local_wcsnlen (arg, precision); - else - tmp_length = local_wcslen (arg); -# else - /* ISO C says about %ls in fprintf: - "If a precision is specified, no more than that - many bytes are written (including shift - sequences, if any), and the array shall contain - a null wide character if, to equal the - multibyte character sequence length given by - the precision, the function would need to - access a wide character one past the end of the - array." - So if there is a precision, we must not use - wcslen. */ - /* This case has already been handled above. */ - abort (); -# endif - } - else -# endif - { -# if WIDE_CHAR_VERSION - /* ISO C says about %s in fwprintf: - "If the precision is not specified or is greater - than the size of the converted array, the - converted array shall contain a null wide - character." - So if there is a precision, we must not use - strlen. */ - /* This case has already been handled above. */ - abort (); -# else - /* ISO C says about %s in fprintf: - "If the precision is not specified or greater - than the size of the array, the array shall - contain a null character." - So if there is a precision, we must not use - strlen. */ - const char *arg = a.arg[dp->arg_index].a.a_string; - - if (has_precision) - tmp_length = local_strnlen (arg, precision); - else - tmp_length = strlen (arg); -# endif - } - break; - - case 'p': - tmp_length = - (unsigned int) (sizeof (void *) * CHAR_BIT - * 0.25 /* binary -> hexadecimal */ - ) - + 1 /* turn floor into ceil */ - + 2; /* account for leading 0x */ - break; - - default: - abort (); - } - - if (!pad_ourselves) - { -# if ENABLE_UNISTDIO - /* Padding considers the number of characters, therefore - the number of elements after padding may be - > max (tmp_length, width) - but is certainly - <= tmp_length + width. */ - tmp_length = xsum (tmp_length, width); -# else - /* Padding considers the number of elements, - says POSIX. */ - if (tmp_length < width) - tmp_length = width; -# endif - } - - tmp_length = xsum (tmp_length, 1); /* account for trailing NUL */ - } + tmp_length = + MAX_ROOM_NEEDED (&a, dp->arg_index, dp->conversion, type, + flags, width, has_precision, precision, + pad_ourselves); if (tmp_length <= sizeof (tmpbuf) / sizeof (TCHAR_T)) tmp = tmpbuf; @@ -5083,15 +5099,44 @@ /* Look at the snprintf() return value. */ if (retcount < 0) { +# if !HAVE_SNPRINTF_RETVAL_C99 /* HP-UX 10.20 snprintf() is doubly deficient: It doesn't understand the '%n' directive, *and* it returns -1 (rather than the length that would have been required) when the - buffer is too small. */ - size_t bigger_need = - xsum (xtimes (allocated, 2), 12); - ENSURE_ALLOCATION (bigger_need); - continue; + buffer is too small. + But a failure at this point can also come + from other reasons than a too small buffer, + such as an invalid wide string argument to + the %ls directive, or possibly an invalid + floating-point argument. */ + size_t tmp_length = + MAX_ROOM_NEEDED (&a, dp->arg_index, + dp->conversion, type, flags, + width, has_precision, + precision, pad_ourselves); + + if (maxlen < tmp_length) + { + /* Make more room. But try to do through + this reallocation only once. */ + size_t bigger_need = + xsum (length, + xsum (tmp_length, + TCHARS_PER_DCHAR - 1) + / TCHARS_PER_DCHAR); + /* And always grow proportionally. + (There may be several arguments, each + needing a little more room than the + previous one.) */ + size_t bigger_need2 = + xsum (xtimes (allocated, 2), 12); + if (bigger_need < bigger_need2) + bigger_need = bigger_need2; + ENSURE_ALLOCATION (bigger_need); + continue; + } +# endif } else count = retcount; @@ -5107,7 +5152,10 @@ if (buf_malloced != NULL) free (buf_malloced); CLEANUP (); - errno = EINVAL; + errno = + (dp->conversion == 'c' || dp->conversion == 's' + ? EILSEQ + : EINVAL); return NULL; } @@ -5494,6 +5542,7 @@ } } +#undef MAX_ROOM_NEEDED #undef TCHARS_PER_DCHAR #undef SNPRINTF #undef USE_SNPRINTF
--- a/m4/vasnprintf.m4 Sat Apr 10 22:17:02 2010 +0200 +++ b/m4/vasnprintf.m4 Sat Apr 10 22:25:31 2010 +0200 @@ -1,4 +1,4 @@ -# vasnprintf.m4 serial 29 +# vasnprintf.m4 serial 31 dnl Copyright (C) 2002-2004, 2006-2010 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -54,6 +54,7 @@ # Prerequisites of lib/vasnprintf.c. AC_DEFUN_ONCE([gl_PREREQ_VASNPRINTF], [ + AC_REQUIRE([AC_C_INLINE]) AC_REQUIRE([AC_FUNC_ALLOCA]) AC_REQUIRE([AC_TYPE_LONG_LONG_INT]) AC_REQUIRE([gt_TYPE_WCHAR_T]) @@ -62,6 +63,17 @@ dnl Use the _snprintf function only if it is declared (because on NetBSD it dnl is defined as a weak alias of snprintf; we prefer to use the latter). AC_CHECK_DECLS([_snprintf], , , [#include <stdio.h>]) + dnl We can avoid a lot of code by assuming that snprintf's return value + dnl conforms to ISO C99. So check that. + AC_REQUIRE([gl_SNPRINTF_RETVAL_C99]) + case "$gl_cv_func_snprintf_retval_c99" in + *yes) + AC_DEFINE([HAVE_SNPRINTF_RETVAL_C99], [1], + [Define if the return value of the snprintf function is the number of + of bytes (excluding the terminating NUL) that would have been produced + if the buffer had been large enough.]) + ;; + esac ]) # Extra prerequisites of lib/vasnprintf.c for supporting 'long double'