DM_GETTEXT

The ID of the dialog item for which you want to retrieve the text.

Pointer to a FarDialogItemDatastructure that receives the text.
If Param2 is NULL this is yet another way to retrieve necessary data size (see DM_GETTEXTLENGTH):

LenData=SendDlgMessage(hDlg,DM_GETTEXT,1,(LONG_PTR)NULL);

is equal to

LenData=SendDlgMessage(hDlg,DM_GETTEXTLENGTH,1,0);

Data size without terminating character '\0'.

Control	Description
All	String data for edit lines, captions for other items. Everything contained in FarDialogItem.Data or FarDialogItem.PtrData.

The DM_GETTEXT message in FAR versions up to (and including) 1.70 beta 3 returned the size INCLUDING the terminating character.