WCSTOMBS(3) | Library Functions Manual | WCSTOMBS(3)

# NAME

`wcstombs` — converts a wide-character string to a multibyte character string

# SYNOPSIS

`#include <stdlib.h>`

size_t
`wcstombs`(char * restrict s, const wchar_t * restrict pwcs, size_t n);

# DESCRIPTION

`wcstombs`() converts the null-terminated wide-character string pointed to by pwcs to the corresponding multibyte character string, and stores up to n bytes in the array pointed to by s. Each character will be converted as if wctomb(3) is continuously called, except the internal state of wctomb(3) will not be affected.

For state-dependent encoding, the `wcstombs`() implies the result multibyte character string pointed to by s always to begin with an initial state.

The behaviour of the `wcstombs`() is affected by the `LC_CTYPE` category of the current locale.

There are special cases:

s == NULL
  The `wcstombs`() function returns the number of bytes to store the whole multibyte character string corresponding to the wide-character string pointed to by pwcs. In this case, n is ignored.
pwcs == NULL
  Undefined (may causes the program to crash).

# RETURN VALUES

`wcstombs`() returns:

0 or positive
  Number of bytes stored in the array pointed to by s. There are no cases that the value returned is greater than n (unless s is a null pointer). If the return value is equal to n, the string pointed to by s will not be null-terminated.
(size_t)-1
  pwcs points the string containing invalid wide character. `wcstombs`() also sets errno to indicate the error.

# ERRORS

`wcstombs`() may cause an error in the following cases:

[`EILSEQ`]
  pwcs Points to the string containing invalid wide character.

# SEE ALSO

setlocale(3), wctomb(3)

# STANDARDS

The `wcstombs`() function conforms to ANSI X3.159-1989 (“ANSI C89”). The restrict qualifier is added at ISO/IEC 9899/1999 (“ISO C99”).

March 29, 2022 | Debian