Header File 

stdlib.h  

Category 

Conversion Routines, Memory and String Manipulation Routines 

Prototype 

size_t mbstowcs(wchar_t *pwcs, const char *s, size_t n); 

Description 

Converts a multibyte string to a wchar_t array. 

The function converts the multibyte string s into the array pointed to by pwcs. No more than n values are stored in the array. If an invalid multibyte sequence is encountered, mbstowcs returns (size_t) -1. 

The pwcs array will not be terminated with a zero value if mbstowcs returns n. 

Return Value 

If an invalid multibyte sequence is encountered, mbstowcs returns (size_t) -1. Otherwise, the function returns the number of array elements modified, not including the terminating code, if any. 

Example  

#include <stdio.h>
#include <stdlib.h>
void main(void)
{
  int x;
  char    *mbst = (char *)malloc(MB_CUR_MAX);
  wchar_t *pwst = L"Hi";
  wchar_t *pwc      = (wchar_t *)malloc(sizeof( wchar_t));
  printf ("Convert to multibyte string:\n");
  x = wcstombs (mbst, pwst, MB_CUR_MAX);
  printf ("\tCharacters converted %u\n",x);
  printf ("\tHEx value of first");
  printf (" multibyte character: %#.4x\n\n", mbst);
  printf ("Convert back to wide character string:\n");
  x = mbstowcs(pwc, mbst, MB_CUR_MAX);
  printf( "\tCharacters converted: %u\n",x);
  printf( "\tHex value of first");
  printf( "wide character: %#.4x\n\n", pwc);
}

Portability