• 0 means no errors or warnings were found during a successful
invocation of the program.
• 2 is returned if errors occur during formatting which do not
prevent completion of the formatting, but which appear to be
manifested by incorrect code (i.e. code which wouldn't
compile).
• 3 is returned if formatting of a file is halted because of an
error with the file which prevents completion of formatting. If
more than one input file was specified, indent continues to the
next file.
• 4 is returned if a serious internal problem occurs and the
entire indent process is terminated, even if all specified
files have not been processed.
• 64 is returned if an invocation problem (like an incorrect
option) prevents any formatting to occur.
