What does File.open() returns?

system · May 13, 2017, 5:22pm


	Attention	Topic was automatically imported from the old Question2Answer platform.
	Asked By	Mudley
	Old Version	Published before Godot 3 was released.

I am curious to know what does the function open() in File returns. I know it is an integer, but of what? My guess is for error checking, but then, why not return Error instead?

system · May 13, 2017, 9:04pm


	Reply From:	avencherus

Should be an Error which is an enumerated type. You can see in the code below it will return parameters invalid, can’t open file, and OK.

github.com

godotengine/godot/blob/df61dc4b2bd54a5a40c515493c76f5a458e5b541/drivers/windows/file_access_windows.cpp#L56


      
          void FileAccessWindows::check_errors() const {
          
          	ERR_FAIL_COND(!f);
          
          	if (feof(f)) {
          
          		last_error = ERR_FILE_EOF;
          	}
          }
          
          Error FileAccessWindows::_open(const String &p_filename, int p_mode_flags) {
          
          	String filename = fix_path(p_filename);
          	if (f)
          		close();
          
          	const wchar_t *mode_string;
          
          	if (p_mode_flags == READ)
          		mode_string = L"rb";
          	else if (p_mode_flags == WRITE)

The enum can be seen here:

github.com

godotengine/godot/blob/df61dc4b2bd54a5a40c515493c76f5a458e5b541/core/error_list.h#L40


      
          #ifndef ERROR_LIST_H
          #define ERROR_LIST_H
          
          /** Error List. Please never compare an error against FAILED
           * Either do result != OK , or !result. This way, Error fail
           * values can be more detailed in the future.
           *
           * This is a generic error list, mainly for organizing a language of returning errors.
           */
          
          enum Error {
          	OK,
          	FAILED, ///< Generic fail error
          	ERR_UNAVAILABLE, ///< What is requested is unsupported/unavailable
          	ERR_UNCONFIGURED, ///< The object being used hasn't been properly set up yet
          	ERR_UNAUTHORIZED, ///< Missing credentials for requested resource
          	ERR_PARAMETER_RANGE_ERROR, ///< Parameter given out of range (5)
          	ERR_OUT_OF_MEMORY, ///< Out of memory
          	ERR_FILE_NOT_FOUND,
          	ERR_FILE_BAD_DRIVE,
          	ERR_FILE_BAD_PATH,