IntControl( 38, p1, p2, 0, 0)
Sets quiet mode.
P1 Meaning
-1 Don't change (just return current setting)
0 Disable quiet mode (default).
1 Enable quiet mode.
p2 = error log filename, or a blank string ("") for no error log.
In "quiet mode":
1. No error messages are displayed. If an error log filename is specified, then error messages will be written to that file.
2. You MUST set the "warning" parameter in any FileCopy or FileMove commands to @FALSE, or else a fatal error will occur.
3. Sounds that would normally be controlled by the Sounds function are suppressed.
Returns previous setting.