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25.3.10 Flags for the argp_help Function

When calling argp_help (see The argp_help Function) or argp_state_help (see Functions For Use in Argp Parsers) the exact output is determined by the flags argument. This should consist of any of the following flags, or’d together:

ARGP_HELP_USAGE ¶

A unix ‘Usage:’ message that explicitly lists all options.

ARGP_HELP_SHORT_USAGE ¶

A unix ‘Usage:’ message that displays an appropriate placeholder to indicate where the options go; useful for showing the non-option argument syntax.

ARGP_HELP_SEE ¶

A ‘Try … for more help’ message; ‘…’ contains the program name and ‘--help’.

ARGP_HELP_LONG ¶

A verbose option help message that gives each option available along with its documentation string.

ARGP_HELP_PRE_DOC ¶

The part of the argp parser doc string preceding the verbose option help.

ARGP_HELP_POST_DOC ¶

The part of the argp parser doc string that following the verbose option help.

ARGP_HELP_DOC ¶

(ARGP_HELP_PRE_DOC | ARGP_HELP_POST_DOC)

ARGP_HELP_BUG_ADDR ¶

A message that prints where to report bugs for this program, if the argp_program_bug_address variable contains this information.

ARGP_HELP_LONG_ONLY ¶

This will modify any output to reflect the ARGP_LONG_ONLY mode.

The following flags are only understood when used with argp_state_help. They control whether the function returns after printing its output, or terminates the program:

ARGP_HELP_EXIT_ERR ¶

This will terminate the program with exit (argp_err_exit_status).

ARGP_HELP_EXIT_OK ¶

This will terminate the program with exit (0).

The following flags are combinations of the basic flags for printing standard messages:

ARGP_HELP_STD_ERR ¶

Assuming that an error message for a parsing error has printed, this prints a message on how to get help, and terminates the program with an error.

ARGP_HELP_STD_USAGE ¶

This prints a standard usage message and terminates the program with an error. This is used when no other specific error messages are appropriate or available.

ARGP_HELP_STD_HELP ¶

This prints the standard response for a ‘--help’ option, and terminates the program successfully.