_mbbtype

Remonter à string.h - Index

Header File

mbstring.h

Category

Classification Routines

Prototype

int _mbbtype(unsigned char ch, int mode);

Description

The _mbbtype function inspects the multibyte argument, character ch, to determine whether it is a single-byte character, or whether ch is the leadbyte or trailing byte in a multibyte character. The _mbbtype function can determine whether ch is an invalid character.

Return Value

The return value depends on the value of ch and the test which you want performed on ch.

The value that _mbbtype returns is one of the following manifest constants, defined in mbctype.h:

Value of mode	Value of ch	Test performed	Return Value
mode != 1	Single byte	Valid single or lead byte	_MBC_SINGLE
mode != 1	Leadbyte	Valid single of lead byte	_MBC_LEAD
mode = 1	Trailbyte	Valid single or trail byte	_MBC_TRAIL
Any value	Any value	Valid character	_MBC_ILLEGAL

Example

#include <mbstring.h>
#include <mbctype.h>
int count_chars(char* input)
{
  int last_type = 0;
  int chars = 0;

  while (*input)
  {
    /* Obtain the type of the current char based on the type of the last one */
    last_type = _mbbtype(*input, last_type);

    /* Consider single and MBCS chars as whole chars. For illegal chars exit with -1 */
    switch (last_type) 
    {
      case _MBC_LEAD:
      case _MBC_SINGLE:
        chars++;
        break;
      case _MBC_ILLEGAL:
        return -1;
    }

    input++;
  }

  /* The number of chars calculated */
  return chars;
}