diff options
| -rw-r--r-- | manual/charset.texi | 23 | ||||
| -rw-r--r-- | stdlib/stdlib.h | 2 | ||||
| -rw-r--r-- | wcsmbs/Makefile | 2 | ||||
| -rw-r--r-- | wcsmbs/tst-mbstowcs.c | 50 |
4 files changed, 71 insertions, 6 deletions
diff --git a/manual/charset.texi b/manual/charset.texi index 9fd0166115..b638323fc2 100644 --- a/manual/charset.texi +++ b/manual/charset.texi @@ -1026,6 +1026,10 @@ stores in the pointer pointed to by @var{src} either a null pointer (if the NUL byte in the input string was reached) or the address of the byte following the last converted multibyte character. +Like @code{mbstowcs} the @var{dst} parameter may be a null pointer and +the function can be used to count the number of wide characters that +would be required. + @pindex wchar.h @code{mbsrtowcs} was introduced in @w{Amendment 1} to @w{ISO C90} and is declared in @file{wchar.h}. @@ -1101,10 +1105,11 @@ successfully converted. Except in the case of an encoding error the return value of the @code{wcsrtombs} function is the number of bytes in all the multibyte -character sequences stored in @var{dst}. Before returning, the state in -the object pointed to by @var{ps} (or the internal object in case -@var{ps} is a null pointer) is updated to reflect the state after the -last conversion. The state is the initial shift state in case the +character sequences which were or would have been (if @var{dst} was +not a null) stored in @var{dst}. Before returning, the state in the +object pointed to by @var{ps} (or the internal object in case @var{ps} +is a null pointer) is updated to reflect the state after the last +conversion. The state is the initial shift state in case the terminating NUL wide character was converted. @pindex wchar.h @@ -1131,6 +1136,10 @@ string @code{*@var{src}} need not be NUL-terminated. But if a NUL byte is found within the @var{nmc} first bytes of the string, the conversion stops there. +Like @code{mbstowcs} the @var{dst} parameter may be a null pointer and +the function can be used to count the number of wide characters that +would be required. + This function is a GNU extension. It is meant to work around the problems mentioned above. Now it is possible to convert a buffer with multibyte character text piece by piece without having to care about @@ -1465,6 +1474,12 @@ mbstowcs_alloc (const char *string) @} @end smallexample +If @var{wstring} is a null pointer then no output is written and the +conversion proceeds as above, and the result is returned. In practice +such behaviour is useful for calculating the exact number of wide +characters required to convert @var{string}. This behaviour of +accepting a null pointer for @var{wstring} is an @w{XPG4.2} extension +that is not specified in @w{ISO C} and is optional in @w{POSIX}. @end deftypefun @deftypefun size_t wcstombs (char *@var{string}, const wchar_t *@var{wstring}, size_t @var{size}) diff --git a/stdlib/stdlib.h b/stdlib/stdlib.h index dd779bd740..f971df4247 100644 --- a/stdlib/stdlib.h +++ b/stdlib/stdlib.h @@ -932,7 +932,7 @@ extern int wctomb (char *__s, wchar_t __wchar) __THROW; /* Convert a multibyte string to a wide char string. */ extern size_t mbstowcs (wchar_t *__restrict __pwcs, const char *__restrict __s, size_t __n) __THROW - __attr_access ((__write_only__, 1, 3)) __attr_access ((__read_only__, 2)); + __attr_access ((__read_only__, 2)); /* Convert a wide char string to multibyte string. */ extern size_t wcstombs (char *__restrict __s, const wchar_t *__restrict __pwcs, size_t __n) diff --git a/wcsmbs/Makefile b/wcsmbs/Makefile index f02167fa58..e638e45522 100644 --- a/wcsmbs/Makefile +++ b/wcsmbs/Makefile @@ -52,7 +52,7 @@ tests := tst-wcstof wcsmbs-tst1 tst-wcsnlen tst-btowc tst-mbrtowc \ tst-c16c32-1 wcsatcliff tst-wcstol-locale tst-wcstod-nan-locale \ tst-wcstod-round test-char-types tst-fgetwc-after-eof \ tst-wcstod-nan-sign tst-c16-surrogate tst-c32-state \ - $(addprefix test-,$(strop-tests)) + $(addprefix test-,$(strop-tests)) tst-mbstowcs include ../Rules diff --git a/wcsmbs/tst-mbstowcs.c b/wcsmbs/tst-mbstowcs.c new file mode 100644 index 0000000000..b48891553e --- /dev/null +++ b/wcsmbs/tst-mbstowcs.c @@ -0,0 +1,50 @@ +/* Test basic mbstowcs including wstring == NULL (Bug 25219). + Copyright (C) 2020 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <stdlib.h> +#include <string.h> +#include <support/check.h> + +static int +do_test (void) +{ + char string[] = { '1', '2', '3' , '4', '5', '\0' }; + size_t len = strlen (string); + wchar_t wstring[] = { L'1', L'2', L'3', L'4', L'5', L'\0' }; +#define NUM_WCHAR 6 + wchar_t wout[NUM_WCHAR]; + size_t result; + + /* The input ASCII string in the C/POSIX locale must convert + to the matching WSTRING. */ + result = mbstowcs (wout, string, NUM_WCHAR); + TEST_VERIFY (result == (NUM_WCHAR - 1)); + TEST_COMPARE_BLOB (wstring, sizeof (wchar_t) * (NUM_WCHAR - 1), + wout, sizeof (wchar_t) * result); + + /* The input ASCII string in the C/POSIX locale must be the + same length when using mbstowcs to compute the length of + the string required in the conversion. Using mbstowcs + in this way is an XSI extension to POSIX. */ + result = mbstowcs (NULL, string, len); + TEST_VERIFY (result == len); + + return 0; +} + +#include <support/test-driver.c> |