mbstowcs

名前

ライブラリ

書式

#include <stdlib.h>

size_t mbstowcs(size_t dsize;
                wchar_t dest[restrict dsize], const char *restrict src,
                size_t dsize);

説明

•

不正なマルチバイト列に遭遇した。この場合には (size_t) -1 を返す。

•

dsize non-L'\0' wide characters have been stored at dest. In this case, the number of wide characters written to dest is returned, but the shift state at this point is lost.

•

The multibyte string has been completely converted, including the terminating null character ('\0'). In this case, the number of wide characters written to dest, excluding the terminating null wide character, is returned.

If dest is NULL, dsize is ignored, and the conversion proceeds as above, except that the converted wide characters are not written out to memory, and that no length limit exists.

In order to avoid the case 2 above, the programmer should make sure dsize is greater than or equal to mbstowcs(NULL,src,0)+1.

The programmer must ensure that there is room for at least dsize wide characters at dest.  

返り値

属性

バージョン

標準規格

歴史

注意

例

$ ./t_mbstowcs de_DE.UTF-8 Grüße!
Length of source string (excluding terminator):
    8 bytes
    6 multibyte characters

Wide character string is: Grüße! (6 characters)
    G alpha upper
    r alpha lower
    ü alpha lower
    ß alpha lower
    e alpha lower
    ! !alpha

プログラムのソース

#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include <wctype.h>

int
main(int argc, char *argv[])
{
    size_t mbslen;      /* Number of multibyte characters in source */
    wchar_t *wcs;       /* Pointer to converted wide character string */

    if (argc < 3) {
        fprintf(stderr, "Usage: %s <locale> <string>\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    /* Apply the specified locale.  */

    if (setlocale(LC_ALL, argv[1]) == NULL) {
        perror("setlocale");
        exit(EXIT_FAILURE);
    }

    /* Calculate the length required to hold argv[2] converted to
       a wide character string.  */

    mbslen = mbstowcs(NULL, argv[2], 0);
    if (mbslen == (size_t) -1) {
        perror("mbstowcs");
        exit(EXIT_FAILURE);
    }

    /* Describe the source string to the user.  */

    printf("Length of source string (excluding terminator):\n");
    printf("    %zu bytes\n", strlen(argv[2]));
    printf("    %zu multibyte characters\n\n", mbslen);

    /* Allocate wide character string of the desired size.  Add 1
       to allow for terminating null wide character (L'\0').  */

    wcs = calloc(mbslen + 1, sizeof(*wcs));
    if (wcs == NULL) {
        perror("calloc");
        exit(EXIT_FAILURE);
    }

    /* Convert the multibyte character string in argv[2] to a
       wide character string.  */

    if (mbstowcs(wcs, argv[2], mbslen + 1) == (size_t) -1) {
        perror("mbstowcs");
        exit(EXIT_FAILURE);
    }

    printf("Wide character string is: %ls (%zu characters)\n",
           wcs, mbslen);

    /* Now do some inspection of the classes of the characters in
       the wide character string.  */

    for (wchar_t *wp = wcs; *wp != 0; wp++) {
        printf("    %lc ", (wint_t) *wp);

        if (!iswalpha(*wp))
            printf("!");
        printf("alpha ");

        if (iswalpha(*wp)) {
            if (iswupper(*wp))
                printf("upper ");

            if (iswlower(*wp))
                printf("lower ");
        }

        putchar('\n');
    }

    exit(EXIT_SUCCESS);
}

関連項目

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