The .ICON extended attribute (EA) specifies the icon to be used for the file representation, for example when the application is minimized. This extended attribute contains the physical icon data used to represent the file object.
If there is no .ICON EA, OS/2 can use the .TYPE entry to determine a default icon to use for the particular file. If there is an .ICON entry, however, it is used instead of the default icon.
The name of this EA consists of the string ".ICON". The value of this EA contains the physical icon data and has the following format:
EAT_ICON data_length data
WORD DWORD
The data is of type BITMAPARRAYFILEHEADER and is used to specify an array of one device-dependent and one device-independent icon bit maps. The GpiLoadBitmap and WinLoadPointer functions support this icon file format.
It is best to provide as much icon information as possible. Ideally, an icon should be 64-by-64 bits in 8-color, device-independent format.
The Icon Editor is used to create the icon, which is saved in an icon file. The .ICON extended attribute for an application is created by the Resource Compiler as part of the compile process by specifying the DEFAULTICON keyword, as in:
DEFAULTICON <filename.ico>This keyword uses the icon definition contained in the specified icon file (FILENAME.ICO) to create the .ICON EA for the application.
Applications store the binary icon data in this extended attribute. To install icons for data files, the applications can use the .ASSOCTABLE extended attribute, or DosSetPathInfo.