slen              149 core/ngx_string.c     size_t                 len, slen;
slen              175 core/ngx_string.c             slen = (size_t) -1;
slen              217 core/ngx_string.c                     slen = va_arg(args, size_t);
slen              252 core/ngx_string.c                 if (slen == (size_t) -1) {
slen              258 core/ngx_string.c                     len = ngx_min(((size_t) (last - buf)), slen);