Lets your program accept command-line options with long names, introduced by --. Standard single-character options are also accepted. Options that start with -- may have an argument appended, following a space or an equals sign (=):
--foo=bar --foo bar
Provides two functions: GetOptions and config.
Sets the variables in optionlist to change the default behavior of GetOptions. The following options are available:
$result = GetOptions(option-descriptions)
Uses descriptions from option-descriptionsto retrieve and process the command-line options with which your Perl program was invoked. The options are taken from @ARGV. After GetOptions has processed the options, @ARGV contains only command-line arguments that were not options. Returns 0 if errors are detected. Each option description consists of two elements:
GetOptions can also take as a first argument a reference to a hash that describes the linkage for the options. The linkage specified in the argument list takes precedence over the one specified in the hash. Thus, the following are equivalent:
%optctl = (size => \$offset); &GetOptions(\%optctl, "size=i");
&GetOptions("size=i" => \$offset);
Each option specifier consists of an option name and possibly an argument specifier. The name can be a name, or a list of names separated by |; the first name in the list is the true name of the option, and the others are treated as aliases. Option names may be invoked with the shortest unique abbreviation. Values for argument specifiers are:
A hyphen (-) by itself is considered an option whose name is the empty string. A double hyphen (--) by itself terminates option processing. Any options following the double hyphen remain in @ARGV when GetOptions returns. If an argument specifier ends with @ (e.g., =s@), then the option is treated as an array.
The special option specifier <> can be used to designate a subroutine to handle non-option arguments. For this specifier to be used, the variable $Getopt::Long::order must have the value of the predefined and exported variable, $PERMUTE. See the description of Getopt::Long::config below.
The linkage specifier can be a reference to any of the following:
If no linkage is explicitly specified, but a hash reference is passed, GetOptions puts the value in the hash. For array options, a reference to an anonymous array is generated.
If no linkage is explicitly specified, and no hash reference is passed, GetOptions puts the value into a global variable named after the option, prefixed by opt_. Characters that are not part of the variable syntax are translated to underscores. For example, --fpp-struct-return sets the variable $opt_fpp_struct_return.
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