/**
* Convert string from one encoding to another, making error checking etc
*
- * @param descriptor conversion descriptor, created in init_iconv()
* @param src pointer to source string (multibyte or singlebyte)
* @param srclen length of the source string in bytes
* @param dest pointer to destination string (multibyte or singlebyte)
* @param destlen maximal length allowed for string
* @returns the number of bytes occupied in the destination
**/
-
size_t convert_string(charset_t from, charset_t to,
void const *src, size_t srclen,
void *dest, size_t destlen)