Topic       : TOS - The Operating System
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Version     : tos.hyp (December 19, 2008)
Subject     : Programmieren/Atari
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Compiled on : Atari
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View Ref-File13.14.1.5  xFSL return codes                                       TOS

All xFSL calls return consistent return codes (return values). A 
negative number represents an error, a positive number (or zero) means 
success or an event.

 Name             Value  Meaning 
 xFS_PARERROR        -9  Parameter error, e.g. call after Rev. 3 
 xFS_LOADERROR       -8  Error when loading an xFSL module 
 xFS_RES_ERROR       -7  Resolution too low (minimum 640x400 pixels) 
 xFS_NO_HANDLE       -6  No VDI handle free 
 xFS_NO_WINDOW       -5  No window(handle) free 
 xFS_NO_FONTS        -4  No fonts loaded 
 xFS_NO_FONTSIZE     -3  Font size not identifiable 
 xFS_ACTIVE          -2  Font-selector is active already 
 xFS_ERROR           -1  General error (memory shortage or similar) 
 xFS_STOP             0  [Cancel] button selected 
 xFS_OK               1  [OK] button selected 
 xFS_HELP             2  [Help] button selected 
 xFS_EVENT            3  AES event occurred 
 xFS_POPUP            4  Changes to user-popup 

These values were chosen to be upwardly compatible to the UFSL font- 
selector (this knows the return codes -4, -3, -2, -1, 0 and 1).

In addition, GEMDOS error messages (values smaller or equal to -32) 
can occur; in particular, xfsl_init can also return the value EINVFN 
(-32) if the font-selector does not support the extended call.

With the xfsl_init call, positive return values correspond to the 
font-selector's window handle (0 means that the font-selector was 
opened as a modal dialog).

It is possible that the list of return codes will be extended in the 
future for further errors (values smaller than -9) or events (values 
greater that 4). This should be respected during the design of the 
program: Unknown errors should lead to an abort, unknown events should 
be ignored.