Updated September 2010
Specifies the primary text (and/or an image specification) that will appear on or in the control. This applies mainly to simple controls like buttons, static text controls, checkboxes, edit boxes, etc. Some controls have no text (such as a rectangle or image), or have so much text (like a Tab control or dialog), that ctext or may used for some other purpose, such as to specify a title or an encoded string of additional parameters. Refer to the topics on specific control types for ctext specifications relative to those controls, in particular:
Also see the opcode table for other specific exceptions based on the opcode.
As a convenience when deleting or clearing controls, you may set ctext to "*" to delete or clear all within the specified srow, scol, erow, ecol coordinates. Or you may specify the control purely by its ctlid and omit all the remaining parameters.
To assign an Accelerator to the control, precede the desired character with an & (e.g. ctext = "Self &Destruct")
The limit on size of the ctext parameter is approximately 3500 bytes (1024 prior to A-Shell 1140 of March 2009). The actual limit is about 4K, less the space used for all of the other AUI_CONTROL parameters. The larger limit will be mainly useful with very large Tab controls (i.e. having many tab panes).
If ctext does not contain a trailing null byte, and it is followed immediately in physical memory by the func parameter, the last byte of ctext will be truncated.