getoptlongint

getoptlongint is a routine found in some command-line parsing libraries that handles long-form options and converts their arguments to a long integer. It is typically used in contexts where programs accept options such as --count=10 or --limit 42 and need the accompanying value as a numeric type for further processing. In many implementations, getoptlongint is part of a broader family of option-parsing facilities that also include short options (getopt) and full-featured long-option parsers (getopt_long); it focuses specifically on options whose arguments are intended to be interpreted as long integers.

The exact API and behavior of getoptlongint can vary by language and library, but common patterns include: supplying a description of valid long options, invoking the routine to advance to the next option in the argument list, and retrieving the numeric value associated with the current option when an argument is present. If an option is encountered that requires an argument, the function will attempt to convert the provided string to a long integer, typically using a base-10 conversion unless otherwise specified. Error handling may report missing arguments, invalid numeric formats, or out-of-range values, either through return codes, error flags, or by setting a global state.

Usage considerations include portability and library availability, as getoptlongint is not part of the POSIX standard and implementations differ between languages and toolchains. Developers choose it when a program’s command-line interface relies on long options with numeric arguments and prefer a dedicated routine over ad hoc parsing. Related concepts include getopt, getopt_long, and general argument parsing utilities.