To obtain the exact length of the text, use the WM_GETTEXT, LB_GETTEXT, or CB_GETLBTEXT messages, or the GetWindowText function. For more information on ANSI and ANSI functions, see Conventions for Function Prototypes.

It can also occur when an application uses the ANSI version of GetWindowTextLength with a window whose window procedure is Unicode, or the Unicode version of GetWindowTextLength with a window whose window procedure is ANSI. To suggest any additions you would like to see made, please contact the author with your request.

Please keep in mind that this site does not encompass the entire API yet, so unfortunately may not find what you are looking for. This behavior can occur when an application uses both ANSI functions and common dialogs, which use Unicode. Below is a categorical list of the API functions currently documented on this web site. If the specified window is a control, the text of the control is copied. The return value, however, will always be at least as large as the actual length of the text you can thus always use it to guide buffer allocation. Copies the text of the specified windows title bar (if it has one) into a buffer. C Signature: DllImport('user32. This occurs with certain mixtures of ANSI and Unicode, and is due to the system allowing for the possible existence of double-byte character set (DBCS) characters within the text. Under certain conditions, the GetWindowTextLength function may return a value that is larger than the actual length of the text. If the target window is owned by the current process, GetWindowTextLength causes a WM_GETTEXTLENGTH message to be sent to the specified window or control. To determine success or failure, clear the most recent error information by calling SetLastError with 0, then call GetLastError. This function does not clear the most recent error information.

Getwindowtext windows api reference