A good C alternative for Boost.Program_options?

Question

Any good alternative written in C to replace Boost.Program_options? Given it's able to parse:

1. Short options like -h
2. Long options like --help --input-file
3. Parse repeated keys/options
4. Accepts key-value pairs: --mysql=/usr/lib
5. Parsing environmental variables and XML/INI files is optional.

Answer 1

If you are okay with the GPL license, you want GNU getopt.

Answer 2

POSIX has getopt, glibc adds getopt_long. Both the links I posted have examples. None of them parses environment variables of XML/INI files, but those two don't really belong with command-line options parsing. A quick google search results in libraries to be able to do those things though.

Answer 3

GLib comes with a commandline option parser that supports your first four requirements, and also a key-value file parser that supports the fifth.