function
mbtowc
<cstdlib>
int mbtowc ( wchar_t * pwc, const char * pmb, size_t max );
Convert multibyte sequence to wide character
The multibyte character pointed by pmb is converted to a value of type wchar_t and stored at the location pointed by pwc. The function returns the length in bytes of the multibyte character.
mbtowc has its own internal shift state, which is altered as necessary only by calls to this function. A call to the function with a null pointer as pmb resets the state (and returns whether multibyte characters are state-dependent).
The behavior of this function depends on the LC_CTYPE category of the selected C locale.
Parameters
- pwc
- Pointer to an object of type wchar_t.
Alternativelly, this argument can be a null pointer, in which case the function does not store the wchar_t translation, but still returns the length in bytes of the multibyte character.
- pmb
- Pointer to the first byte of a multibyte character.
Alternativelly, this argument can be a null pointer, in which case the function resets its internal shift state to the initial value and returns whether multibyte characters have a state-dependent encoding.
- max
- Maximum number of bytes to be checked for character length.
No more than MB_CUR_MAX characters are examined in any case.
size_t is an unsigned integral type.
Return Value
If the argument passed as pmb is not a null pointer, the size in bytes of the multibyte character pointed by pmb is returned when it forms a valid multibyte character and is not the terminating null character. If it is the terminating null character, the function returns zero, and in the case they do not form a valid multibyte character, -1 is returned.
If the argument passed as pmb is a null pointer, the function returns a nonzero value if multibyte character encodings are state-dependent, and zero otherwise.
Example
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/* mbtowc example */
#include <stdio.h>
#include <stdlib.h>
void printbuffer (const char* pt, size_t max)
{
int length;
wchar_t dest;
mbtowc (NULL, NULL, 0); /* reset mbtowc */
while (max>0) {
length = mbtowc(&dest,pt,max);
if (length<1) break;
printf ("[%lc]",dest);
pt+=length; max-=length;
}
}
int main()
{
const char str [] = "mbtowc example";
printbuffer (str,sizeof(str));
return 0;
}
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Function printbuffer prints a multibyte string character by character.
The example uses a trivial string on the "C" locale, but locales supporting multibyte string are supported by the function.
Output:
[m][b][t][o][w][c][ ][e][x][a][m][p][l][e]
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See also
- mblen
- Get length of multibyte character (function
)
- wctomb
- Convert wide character to multibyte sequence (function
)
- mbstowcs
- Convert multibyte string to wide-character string (function
)
- wcstombs
- Convert wide-character string to multibyte string (function
)