signature        2190 http/ngx_http_core_module.c     sr->signature = NGX_HTTP_MODULE;
signature         307 http/ngx_http_request.c     r->signature = NGX_HTTP_MODULE;
signature         347 http/ngx_http_request.h     uint32_t                          signature;         /* "HTTP" */
signature         182 mail/ngx_mail.h     uint32_t                signature;         /* "MAIL" */