[Scrap] length of characters (I/O Function)

strlen, strlen_l, wcslen, wcslen_l, _mbslen, _mbslen_l, _mbstrlen, _mbstrlen_l

 prototype

size_t strlen( const char *str );

size_t strlen_l( const char *str, _locale_t locale );

size_t wcslen( const wchar_t *str );

size_t wcslen_l( const wchar_t *str, _locale_t locale );

size_t _mbslen( const unsigned char *str );

size_t _mbslen_l( const unsigned char *str, _locale_t locale );

 size_t _mbstrlen( const char *str );

 size_t _mbstrlen_l( const char *str, _locale_t locale );

  Parameters

str : Null-terminated string.

locale : Locale to use.

Return Value

Each of these functions returns the number of characters in str, excluding the terminal NULL. No return value is reserved to indicate an error, except for _mbstrlen, which returns -1 if the string contains an invalid multibyte character.

 Example from MSDN

// crt_strlen.c

// Determine the length of a string. For the multi-byte character

// example to work correctly, the Japanese language support for

// non-Unicode programs must be enabled by the operating system.

#include <string.h>

#include <locale.h>

int main()

{

   char* str1 = "Count.";

   wchar_t* wstr1 = L"Count.";

   char * mbstr1;

   char * locale_string;

   // strlen gives the length of single-byte character string

   printf("Length of '%s' : %d\n", str1, strlen(str1) );

   // wstrlen gives the length of a wide character string

   wprintf(L"Length of '%s' : %d\n", wstr1, wcslen(wstr1) );

   // A multibyte string: [A] [B] [C] [katakana A] [D] [\0]

   // in Code Page 932. For this example to work correctly,

   // the Japanese language support must be enabled by the

   // operating system.

   mbstr1 = "ABC" "\x83\x40" "D";

   locale_string = setlocale(LC_CTYPE, "Japanese_Japan");

   if (locale_string == NULL)

   {

      printf("Japanese locale not enabled. Exiting.\n");

      exit(1);

   }

   else

   {

      printf("Locale set to %s\n", locale_string);

   }

   // _mbslen will recognize the Japanese multibyte character if the

   // current locale used by the operating system is Japanese

   printf("Length of '%s' : %d\n", mbstr1, _mbslen(mbstr1) );

   // _mbstrlen will recognize the Japanese multibyte character

   // since the CRT locale is set to Japanese even if the OS locale

   // isnot.

   printf("Length of '%s' : %d\n", mbstr1, _mbstrlen(mbstr1) );

   printf("Bytes in '%s' : %d\n", mbstr1, strlen(mbstr1) );  

 

}

 Its result

Length of 'Count.' : 6

Length of 'Count.' : 6

Length of 'ABCァD' : 5

Length of 'ABCァD' : 5

Bytes in 'ABCァD' : 6

You can see the same thing at this page:

http://msdn.microsoft.com/en-us/library/78zh94ax.aspx

from MSDN