SvIV(sv_len), buf_len);
(int)SvIV(sv_len), buf_len);
apr_size_t mpxs_apr_socket_send(pTHX_ apr_socket_t *socket,                                SV *sv_buf, SV *sv_len){    apr_size_t buf_len;    char *buffer = SvPV(sv_buf, buf_len);    if (sv_len) {        if (buf_len < SvIV(sv_len)) {            Perl_croak(aTHX_ "the 3rd arg (%d) is bigger than the "                       "length (%d) of the 2nd argument",                       SvIV(sv_len), buf_len);        }        buf_len = SvIV(sv_len);    }    MP_RUN_CROAK(apr_socket_send(socket, buffer, &buf_len),                 "APR::Socket::send");    return buf_len;}