modules/http/http_filters.c:837: error: UNINITIALIZED_VALUE
  The value read from res was never initialized.

modules/http/http_filters.c:837:13: 
835.         }
836. 
837.         if (res < 0) {
                 ^
838.             return HTTP_BAD_REQUEST;
839.         }

AP_DECLARE_NONSTD(int) ap_send_http_trace(request_rec *r)
{
    core_server_config *conf;
    int rv;
    apr_bucket_brigade *bb;
    header_struct h;
    apr_bucket *b;
    int body;
    char *bodyread, *bodyoff;
    apr_size_t bodylen = 0;
    apr_size_t bodybuf;
    long res;
    if (r->method_number != M_TRACE) {
        return DECLINED;
    }
    while (r->prev) {
        r = r->prev;
    }
    conf = (core_server_config *)ap_get_module_config(r->server->module_config,
                                                      &core_module);
    if (conf->trace_enable == AP_TRACE_DISABLE) {
	apr_table_setn(r->notes, "error-notes",
                      "TRACE denied by server configuration");
        return HTTP_FORBIDDEN;
    }
    if (conf->trace_enable == AP_TRACE_EXTENDED)
        body = REQUEST_CHUNKED_DECHUNK;
    else
        body = REQUEST_NO_BODY;
    if ((rv = ap_setup_client_block(r, body))) {
        if (rv == HTTP_REQUEST_ENTITY_TOO_LARGE)
    	    apr_table_setn(r->notes, "error-notes",
                          "TRACE with a request body is not allowed");
        return rv;
    }
    if (ap_should_client_block(r)) {
        if (r->remaining > 0) {
            if (r->remaining > 65536) {
	        apr_table_setn(r->notes, "error-notes",
                       "Extended TRACE request bodies cannot exceed 64k\n");
                return HTTP_REQUEST_ENTITY_TOO_LARGE;
            }
            bodybuf = (apr_size_t)r->remaining + 32;
        }
        else {
            bodybuf = 73730;
        }
        bodyoff = bodyread = apr_palloc(r->pool, bodybuf);
        while ((!bodylen || bodybuf >= 32) &&
               (res = ap_get_client_block(r, bodyoff, bodybuf)) > 0) {
            bodylen += res;
            bodybuf -= res;
            bodyoff += res;
        }
        if (res > 0 && bodybuf < 32) {
            while (ap_get_client_block(r, bodyread, bodylen) > 0)
                ;
	    apr_table_setn(r->notes, "error-notes",
                   "Extended TRACE request bodies cannot exceed 64k\n");
            return HTTP_REQUEST_ENTITY_TOO_LARGE;
        }
        if (res < 0) {
            return HTTP_BAD_REQUEST;
        }
    }
    ap_set_content_type(r, "message/http");
    bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
    apr_brigade_putstrs(bb, NULL, NULL, r->the_request, CRLF, NULL);
    h.pool = r->pool;
    h.bb = bb;
    apr_table_do((int (*) (void *, const char *, const char *))
                 form_header_field, (void *) &h, r->headers_in, NULL);
    apr_brigade_puts(bb, NULL, NULL, CRLF);
    if (bodylen) {
        b = apr_bucket_pool_create(bodyread, bodylen,
                                   r->pool, bb->bucket_alloc);
        APR_BRIGADE_INSERT_TAIL(bb, b);
    }
    ap_pass_brigade(r->output_filters,  bb);
    return DONE;
}
['AP_DECLARE_NONSTD(int) ap_send_http_trace(request_rec *r)\n{\n    core_server_config *conf;\n    int rv;\n    apr_bucket_brigade *bb;\n    header_struct h;\n    apr_bucket *b;\n    int body;\n    char *bodyread, *bodyoff;\n    apr_size_t bodylen = 0;\n    apr_size_t bodybuf;\n    long res;\n    if (r->method_number != M_TRACE) {\n        return DECLINED;\n    }\n    while (r->prev) {\n        r = r->prev;\n    }\n    conf = (core_server_config *)ap_get_module_config(r->server->module_config,\n                                                      &core_module);\n    if (conf->trace_enable == AP_TRACE_DISABLE) {\n\tapr_table_setn(r->notes, "error-notes",\n                      "TRACE denied by server configuration");\n        return HTTP_FORBIDDEN;\n    }\n    if (conf->trace_enable == AP_TRACE_EXTENDED)\n        body = REQUEST_CHUNKED_DECHUNK;\n    else\n        body = REQUEST_NO_BODY;\n    if ((rv = ap_setup_client_block(r, body))) {\n        if (rv == HTTP_REQUEST_ENTITY_TOO_LARGE)\n    \t    apr_table_setn(r->notes, "error-notes",\n                          "TRACE with a request body is not allowed");\n        return rv;\n    }\n    if (ap_should_client_block(r)) {\n        if (r->remaining > 0) {\n            if (r->remaining > 65536) {\n\t        apr_table_setn(r->notes, "error-notes",\n                       "Extended TRACE request bodies cannot exceed 64k\\n");\n                return HTTP_REQUEST_ENTITY_TOO_LARGE;\n            }\n            bodybuf = (apr_size_t)r->remaining + 32;\n        }\n        else {\n            bodybuf = 73730;\n        }\n        bodyoff = bodyread = apr_palloc(r->pool, bodybuf);\n        while ((!bodylen || bodybuf >= 32) &&\n               (res = ap_get_client_block(r, bodyoff, bodybuf)) > 0) {\n            bodylen += res;\n            bodybuf -= res;\n            bodyoff += res;\n        }\n        if (res > 0 && bodybuf < 32) {\n            while (ap_get_client_block(r, bodyread, bodylen) > 0)\n                ;\n\t    apr_table_setn(r->notes, "error-notes",\n                   "Extended TRACE request bodies cannot exceed 64k\\n");\n            return HTTP_REQUEST_ENTITY_TOO_LARGE;\n        }\n        if (res < 0) {\n            return HTTP_BAD_REQUEST;\n        }\n    }\n    ap_set_content_type(r, "message/http");\n    bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);\n    apr_brigade_putstrs(bb, NULL, NULL, r->the_request, CRLF, NULL);\n    h.pool = r->pool;\n    h.bb = bb;\n    apr_table_do((int (*) (void *, const char *, const char *))\n                 form_header_field, (void *) &h, r->headers_in, NULL);\n    apr_brigade_puts(bb, NULL, NULL, CRLF);\n    if (bodylen) {\n        b = apr_bucket_pool_create(bodyread, bodylen,\n                                   r->pool, bb->bucket_alloc);\n        APR_BRIGADE_INSERT_TAIL(bb, b);\n    }\n    ap_pass_brigade(r->output_filters,  bb);\n    return DONE;\n}']