Bruno Haible wrote:
> You can assume that mbrtowc returns
> 0 if and only if the multibyte sequence is a NUL byte - but you had
> chosen srcend in such a way that this would not happen in the loop.

Thanks for the correction. I mistakenly thought that C allows multibyte 
encodings in which a null wide character's multibyte representation contains an 
all-bits-zero byte. I installed the attached to omit the unnecessary test.