Conversion functions

Developer's Topics
Chapter 2, Complying with standard C

ANSI C provides five library functions that manage multibyte characters and wide characters:

 mblen()      length of next multibyte character
 mbtowc()     convert multibyte character to wide character
 wctomb()     convert wide character to multibyte character
 mbstowcs()   convert multibyte character string to wide character string
 wcstombs()   convert wide character string to multibyte character string

The behavior of all of these functions depends on the current locale.

NOTE: See the setlocale() function in ``Internationalization''.

It is expected that vendors providing compilation systems targeted to this market will supply many more string-like functions to simplify the handling of wide character strings. However, for most application programs, there is no need to convert any multibyte characters to or from wide characters. Programs such as diff, for example, will read in and write out multibyte characters, needing only to check for an exact byte-for-byte match. More complicated programs (such as grep) that use regular expression pattern matching, may need to understand multibyte characters, but only the common set of functions that manages the regular expression needs this knowledge. The program grep itself requires no other special multibyte character handling.