PHP_HTTP_API php_http_cache_status_t php_http_env_is_response_cached_by_etag(zval *options, const char *header_str, size_t header_len TSRMLS_DC);
PHP_HTTP_API php_http_cache_status_t php_http_env_is_response_cached_by_last_modified(zval *options, const char *header_str, size_t header_len TSRMLS_DC);
PHP_HTTP_API php_http_cache_status_t php_http_env_is_response_cached_by_etag(zval *options, const char *header_str, size_t header_len TSRMLS_DC);
PHP_HTTP_API php_http_cache_status_t php_http_env_is_response_cached_by_last_modified(zval *options, const char *header_str, size_t header_len TSRMLS_DC);