C library function - mbstowcs()

Description

The C library function size_t mbstowcs(schar_t *pwcs, const char *str, size_t n) converts the string of multi-byte characters pointed to, by the argument str to the array pointed to by pwcs.

Declaration

Following is the declaration for mbstowcs() function.

size_t mbstowcs(schar_t *pwcs, const char *str, size_t n)

Parameters

• pwcs − This is the pointer to an array of wchar_t elements that is long enough to store a wide string max characters long.

• str − This is the C multi-byte character string to be interpreted.

• n − This is the maximum number of wchar_t characters to be interpreted.

Return Value

This function returns the number of characters translated, excluding the ending null-character. If an invalid multi-byte character is encountered, a -1 value is returned.

Example

The following example shows the usage of mbstowcs() function.

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

int main () {
   int len;
   char *pmbnull  = NULL;
   char *pmb = (char *)malloc( MB_CUR_MAX );
   wchar_t *pwc = L"Hi";
   wchar_t *pwcs = (wchar_t *)malloc( sizeof( wchar_t ));

   printf("Converting to multibyte string\n");
   len = wcstombs( pmb, pwc, MB_CUR_MAX);
   printf("Characters converted %d\n", len);
   printf("Hex value of first multibyte character: %#.4x\n", pmb);
   
   printf("Converting back to Wide-Character string\n");
   len = mbstowcs( pwcs, pmb, MB_CUR_MAX);
   printf("Characters converted %d\n", len);
   printf("Hex value of first wide character %#.4x\n\n", pwcs);
   
   return(0);
}

Let us compile and run the above program that will produce the following result −

Converting to multibyte string
Characters converted 1
Hex value of first multibyte character: 0x19a60010
Converting back to Wide-Character string
Characters converted 1
Hex value of first wide character 0x19a60030