Convert a wide-character string to a character string (restartable).
Standard library (libc.a)
#include <wchar.h>size_t wcsrtombs (char * dst, const wchar_t ** src, size_t len, mbstate_t * ps);
size_t wcsnrtombs (char * dst, const wchar_t ** src, size_t nwc, size_t len, mbstate_t * ps);The wcsrtombs function converts a sequence of wide-characters from the array indirectly pointed to by src into a sequence of corresponding characters, beginning in the conversion state described by the object pointed to by ps.If dst is not a null pointer, the converted characters are then stored into the array pointed to by dst. Conversion continues up to and including a terminating null wide-character, which is also stored. Conversion stops earlier in the following cases:
Each conversion takes place as if by a call to the wcrtomb function.
If dst is not a null pointer, the pointer object pointed to by src is assigned either a null pointer (if conversion stopped due to reaching a terminating null wide-character) or the address just past the last wide-character converted (if any). If conversion stopped due to reaching a terminating null wide-character, the resulting state described is the initial conversion state.
If ps is a null pointer, the wcsrtombs function uses its own internal mbstate_t object, which is initialised at program startup to the initial conversion state. Otherwise, the mbstate_t object pointed to by ps is used to completely describe the current conversion state of the associated character sequence. The implementation will behave as if no function defined in this specification calls wcsrtombs.
The wcsnrtombs function is equivalent to the wcsrtombs function, except that the conversion is limited to the first nwc wide characters.
The behavior of this function is affected by the LC_CTYPE category of the current locale.
If conversion stops because a code is reached that does not correspond to a valid character, an encoding error occurs. In this case, the wcsrtombs and wcsnrtombs functions store the value of the macro EILSEQ in errno and returns (size_t)-1; the conversion state is undefined. Otherwise, the wcsrtombs and wcsnrtombs functions return the number of bytes in the resulting character sequence, not including the terminating null (if any).
The wcsrtombs function may fail if:
| Item | Description |
|---|---|
| EINVAL | ps points to an object that contains an invalid conversion state. |
| EILSEQ | A wide-character code does not correspond to a valid character. |