Man page sez it should be

       size_t iconv (iconv_t cd,
                     const char* * inbuf, size_t * inbytesleft,
                     char* * outbuf, size_t * outbytesleft);

while the iconv.h declaration is:

extern size_t iconv (iconv_t __cd, char **__restrict __inbuf,
                     size_t *__restrict __inbytesleft,
                     char **__restrict __outbuf,
                     size_t *__restrict __outbytesleft);

That is, missing const propery on inbuf. Judging from the semantics of
the function, I'd say it should be const like the man page suggests.

Jesper