# Civetweb API Reference ### `mg_send_http_error( conn, status_code, fmt, ... );` ### Parameters | Parameter | Type | Description | | :--- | :--- | :--- | |**`conn`**|`struct mg_connection *`|The connection over which the data must be sent| |**`status_code`**|`int`|The HTTP status code (see HTTP standard)| |**`fmt`**|`const char *`|Format string for an error message| |**`...`**|*various*|Parameters as specified in the format string| ### Return Value | Type | Description | |`int`| An integer indicating success (>=0) or failure (<0) | ### Description The function `mg_send_http_error()` can be used to send HTTP error messages from a server to a client. The `status_code` must be one of the predefined HTTP standard error codes (e.g., "404" for "Not Found"). The status text (e.g., "Not Found") for standard error codes is known by this function. A body of the error message, to explain the error in more detail, can be specified using the `fmt` format specifier and additional arguments. The `fmt` format specifier works like for the `printf()` function in the standard C library. ### See Also * [`mg_send_http_ok();`](mg_send_http_ok.md) * [`mg_send_http_redirect();`](mg_send_http_redirect.md)