25.3.10 Flags for the argp_help Function
When calling argp_help (see Argp Help) or
argp_state_help (see Argp Helper Functions) 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.