A good C alternative for Boost.Program_options?

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 开发者_StackOverflowfiles is optional.

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

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

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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.