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diff --git a/manual/argp.texi b/manual/argp.texi deleted file mode 100644 index bca3ca5ed9..0000000000 --- a/manual/argp.texi +++ /dev/null @@ -1,1349 +0,0 @@ -@node Argp, Suboptions, Getopt, Parsing Program Arguments -@need 5000 -@section Parsing Program Options with Argp -@cindex argp (program argument parser) -@cindex argument parsing with argp -@cindex option parsing with argp - -@dfn{Argp} is an interface for parsing unix-style argument vectors. -@xref{Program Arguments}. - -Argp provides features unavailable in the more commonly used -@code{getopt} interface. These features include automatically producing -output in response to the @samp{--help} and @samp{--version} options, as -described in the GNU coding standards. Using argp makes it less likely -that programmers will neglect to implement these additional options or -keep them up to date. - -Argp also provides the ability to merge several independently defined -option parsers into one, mediating conflicts between them and making the -result appear seamless. A library can export an argp option parser that -user programs might employ in conjunction with their own option parsers, -resulting in less work for the user programs. Some programs may use only -argument parsers exported by libraries, thereby achieving consistent and -efficient option-parsing for abstractions implemented by the libraries. - -@pindex argp.h -The header file @file{<argp.h>} should be included to use argp. - -@subsection The @code{argp_parse} Function - -The main interface to argp is the @code{argp_parse} function. In many -cases, calling @code{argp_parse} is the only argument-parsing code -needed in @code{main}. -@xref{Program Arguments}. - -@comment argp.h -@comment GNU -@deftypefun {error_t} argp_parse (const struct argp *@var{argp}, int @var{argc}, char **@var{argv}, unsigned @var{flags}, int *@var{arg_index}, void *@var{input}) -@safety{@prelim{}@mtunsafe{@mtasurace{:argpbuf} @mtslocale{} @mtsenv{}}@asunsafe{@ascuheap{} @ascuintl{} @asulock{} @asucorrupt{}}@acunsafe{@acsmem{} @aculock{} @acucorrupt{}}} -@c Optionally alloca()tes standard help options, initializes the parser, -@c then parses individual args in a loop, and then finalizes. -@c parser_init -@c calc_sizes ok -@c option_is_end ok -@c malloc @ascuheap @acsmem -@c parser_convert @mtslocale -@c convert_options @mtslocale -@c option_is_end ok -@c option_is_short ok -@c isprint, but locale may change within the loop -@c find_long_option ok -@c group_parse -@c group->parser (from argp->parser) -@c parser_parse_next -@c getopt_long(_only)_r many issues, same as non_r minus @mtasurace -@c parser_parse_arg -@c group_parse dup -@c parser_parse_opt -@c group_parse dup -@c argp_error dup @mtasurace:argpbuf @mtsenv @mtslocale @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock -@c dgettext (bad key error) dup @mtsenv @asucorrupt @ascuheap @asulock @ascudlopen @acucorrupt @aculock @acsfd @acsmem -@c parser_finalize -@c group_parse -@c fprintf dup @mtslocale @asucorrupt @aculock @acucorrupt [no @ascuheap @acsmem] -@c dgettext dup @mtsenv @asucorrupt @ascuheap @asulock @ascudlopen @acucorrupt @aculock @acsfd @acsmem -@c arg_state_help -@c free dup @ascuhelp @acsmem -The @code{argp_parse} function parses the arguments in @var{argv}, of -length @var{argc}, using the argp parser @var{argp}. @xref{Argp -Parsers}. Passing a null pointer for @var{argp} is the same as using -a @code{struct argp} containing all zeros. - -@var{flags} is a set of flag bits that modify the parsing behavior. -@xref{Argp Flags}. @var{input} is passed through to the argp parser -@var{argp}, and has meaning defined by @var{argp}. A typical usage is -to pass a pointer to a structure which is used for specifying -parameters to the parser and passing back the results. - -Unless the @code{ARGP_NO_EXIT} or @code{ARGP_NO_HELP} flags are included -in @var{flags}, calling @code{argp_parse} may result in the program -exiting. This behavior is true if an error is detected, or when an -unknown option is encountered. @xref{Program Termination}. - -If @var{arg_index} is non-null, the index of the first unparsed option -in @var{argv} is returned as a value. - -The return value is zero for successful parsing, or an error code -(@pxref{Error Codes}) if an error is detected. Different argp parsers -may return arbitrary error codes, but the standard error codes are: -@code{ENOMEM} if a memory allocation error occurred, or @code{EINVAL} if -an unknown option or option argument is encountered. -@end deftypefun - -@menu -* Globals: Argp Global Variables. Global argp parameters. -* Parsers: Argp Parsers. Defining parsers for use with @code{argp_parse}. -* Flags: Argp Flags. Flags that modify the behavior of @code{argp_parse}. -* Help: Argp Help. Printing help messages when not parsing. -* Examples: Argp Examples. Simple examples of programs using argp. -* Customization: Argp User Customization. - Users may control the @samp{--help} output format. -@end menu - -@node Argp Global Variables, Argp Parsers, , Argp -@subsection Argp Global Variables - -These variables make it easy for user programs to implement the -@samp{--version} option and provide a bug-reporting address in the -@samp{--help} output. These are implemented in argp by default. - -@comment argp.h -@comment GNU -@deftypevar {const char *} argp_program_version -If defined or set by the user program to a non-zero value, then a -@samp{--version} option is added when parsing with @code{argp_parse}, -which will print the @samp{--version} string followed by a newline and -exit. The exception to this is if the @code{ARGP_NO_EXIT} flag is used. -@end deftypevar - -@comment argp.h -@comment GNU -@deftypevar {const char *} argp_program_bug_address -If defined or set by the user program to a non-zero value, -@code{argp_program_bug_address} should point to a string that will be -printed at the end of the standard output for the @samp{--help} option, -embedded in a sentence that says @samp{Report bugs to @var{address}.}. -@end deftypevar - -@need 1500 -@comment argp.h -@comment GNU -@defvar argp_program_version_hook -If defined or set by the user program to a non-zero value, a -@samp{--version} option is added when parsing with @code{arg_parse}, -which prints the program version and exits with a status of zero. This -is not the case if the @code{ARGP_NO_HELP} flag is used. If the -@code{ARGP_NO_EXIT} flag is set, the exit behavior of the program is -suppressed or modified, as when the argp parser is going to be used by -other programs. - -It should point to a function with this type of signature: - -@smallexample -void @var{print-version} (FILE *@var{stream}, struct argp_state *@var{state}) -@end smallexample - -@noindent -@xref{Argp Parsing State}, for an explanation of @var{state}. - -This variable takes precedence over @code{argp_program_version}, and is -useful if a program has version information not easily expressed in a -simple string. -@end defvar - -@comment argp.h -@comment GNU -@deftypevar error_t argp_err_exit_status -This is the exit status used when argp exits due to a parsing error. If -not defined or set by the user program, this defaults to: -@code{EX_USAGE} from @file{<sysexits.h>}. -@end deftypevar - -@node Argp Parsers, Argp Flags, Argp Global Variables, Argp -@subsection Specifying Argp Parsers - -The first argument to the @code{argp_parse} function is a pointer to a -@code{struct argp}, which is known as an @dfn{argp parser}: - -@comment argp.h -@comment GNU -@deftp {Data Type} {struct argp} -This structure specifies how to parse a given set of options and -arguments, perhaps in conjunction with other argp parsers. It has the -following fields: - -@table @code -@item const struct argp_option *options -A pointer to a vector of @code{argp_option} structures specifying which -options this argp parser understands; it may be zero if there are no -options at all. @xref{Argp Option Vectors}. - -@item argp_parser_t parser -A pointer to a function that defines actions for this parser; it is -called for each option parsed, and at other well-defined points in the -parsing process. A value of zero is the same as a pointer to a function -that always returns @code{ARGP_ERR_UNKNOWN}. @xref{Argp Parser -Functions}. - -@item const char *args_doc -If non-zero, a string describing what non-option arguments are called by -this parser. This is only used to print the @samp{Usage:} message. If -it contains newlines, the strings separated by them are considered -alternative usage patterns and printed on separate lines. Lines after -the first are prefixed by @samp{ or: } instead of @samp{Usage:}. - -@item const char *doc -If non-zero, a string containing extra text to be printed before and -after the options in a long help message, with the two sections -separated by a vertical tab (@code{'\v'}, @code{'\013'}) character. By -convention, the documentation before the options is just a short string -explaining what the program does. Documentation printed after the -options describe behavior in more detail. - -@item const struct argp_child *children -A pointer to a vector of @code{argp_child} structures. This pointer -specifies which additional argp parsers should be combined with this -one. @xref{Argp Children}. - -@item char *(*help_filter)(int @var{key}, const char *@var{text}, void *@var{input}) -If non-zero, a pointer to a function that filters the output of help -messages. @xref{Argp Help Filtering}. - -@item const char *argp_domain -If non-zero, the strings used in the argp library are translated using -the domain described by this string. If zero, the current default domain -is used. - -@end table -@end deftp - -Of the above group, @code{options}, @code{parser}, @code{args_doc}, and -the @code{doc} fields are usually all that are needed. If an argp -parser is defined as an initialized C variable, only the fields used -need be specified in the initializer. The rest will default to zero due -to the way C structure initialization works. This design is exploited in -most argp structures; the most-used fields are grouped near the -beginning, the unused fields left unspecified. - -@menu -* Options: Argp Option Vectors. Specifying options in an argp parser. -* Argp Parser Functions:: Defining actions for an argp parser. -* Children: Argp Children. Combining multiple argp parsers. -* Help Filtering: Argp Help Filtering. Customizing help output for an argp parser. -@end menu - -@node Argp Option Vectors, Argp Parser Functions, Argp Parsers, Argp Parsers -@subsection Specifying Options in an Argp Parser - -The @code{options} field in a @code{struct argp} points to a vector of -@code{struct argp_option} structures, each of which specifies an option -that the argp parser supports. Multiple entries may be used for a single -option provided it has multiple names. This should be terminated by an -entry with zero in all fields. Note that when using an initialized C -array for options, writing @code{@{ 0 @}} is enough to achieve this. - -@comment argp.h -@comment GNU -@deftp {Data Type} {struct argp_option} -This structure specifies a single option that an argp parser -understands, as well as how to parse and document that option. It has -the following fields: - -@table @code -@item const char *name -The long name for this option, corresponding to the long option -@samp{--@var{name}}; this field may be zero if this option @emph{only} -has a short name. To specify multiple names for an option, additional -entries may follow this one, with the @code{OPTION_ALIAS} flag -set. @xref{Argp Option Flags}. - -@item int key -The integer key provided by the current option to the option parser. If -@var{key} has a value that is a printable @sc{ascii} character (i.e., -@code{isascii (@var{key})} is true), it @emph{also} specifies a short -option @samp{-@var{char}}, where @var{char} is the @sc{ascii} character -with the code @var{key}. - -@item const char *arg -If non-zero, this is the name of an argument associated with this -option, which must be provided (e.g., with the -@samp{--@var{name}=@var{value}} or @samp{-@var{char} @var{value}} -syntaxes), unless the @code{OPTION_ARG_OPTIONAL} flag (@pxref{Argp -Option Flags}) is set, in which case it @emph{may} be provided. - -@item int flags -Flags associated with this option, some of which are referred to above. -@xref{Argp Option Flags}. - -@item const char *doc -A documentation string for this option, for printing in help messages. - -If both the @code{name} and @code{key} fields are zero, this string -will be printed tabbed left from the normal option column, making it -useful as a group header. This will be the first thing printed in its -group. In this usage, it's conventional to end the string with a -@samp{:} character. - -@item int group -Group identity for this option. - -In a long help message, options are sorted alphabetically within each -group, and the groups presented in the order 0, 1, 2, @dots{}, @var{n}, -@minus{}@var{m}, @dots{}, @minus{}2, @minus{}1. - -Every entry in an options array with this field 0 will inherit the group -number of the previous entry, or zero if it's the first one. If it's a -group header with @code{name} and @code{key} fields both zero, the -previous entry + 1 is the default. Automagic options such as -@samp{--help} are put into group @minus{}1. - -Note that because of C structure initialization rules, this field often -need not be specified, because 0 is the correct value. -@end table -@end deftp - - -@menu -* Flags: Argp Option Flags. Flags for options. -@end menu - -@node Argp Option Flags, , , Argp Option Vectors -@subsubsection Flags for Argp Options - -The following flags may be or'd together in the @code{flags} field of a -@code{struct argp_option}. These flags control various aspects of how -that option is parsed or displayed in help messages: - - -@vtable @code -@comment argp.h -@comment GNU -@item OPTION_ARG_OPTIONAL -The argument associated with this option is optional. - -@comment argp.h -@comment GNU -@item OPTION_HIDDEN -This option isn't displayed in any help messages. - -@comment argp.h -@comment GNU -@item OPTION_ALIAS -This option is an alias for the closest previous non-alias option. This -means that it will be displayed in the same help entry, and will inherit -fields other than @code{name} and @code{key} from the option being -aliased. - - -@comment argp.h -@comment GNU -@item OPTION_DOC -This option isn't actually an option and should be ignored by the actual -option parser. It is an arbitrary section of documentation that should -be displayed in much the same manner as the options. This is known as a -@dfn{documentation option}. - -If this flag is set, then the option @code{name} field is displayed -unmodified (e.g., no @samp{--} prefix is added) at the left-margin where -a @emph{short} option would normally be displayed, and this -documentation string is left in its usual place. For purposes of -sorting, any leading whitespace and punctuation is ignored, unless the -first non-whitespace character is @samp{-}. This entry is displayed -after all options, after @code{OPTION_DOC} entries with a leading -@samp{-}, in the same group. - -@comment argp.h -@comment GNU -@item OPTION_NO_USAGE -This option shouldn't be included in `long' usage messages, but should -still be included in other help messages. This is intended for options -that are completely documented in an argp's @code{args_doc} -field. @xref{Argp Parsers}. Including this option in the generic usage -list would be redundant, and should be avoided. - -For instance, if @code{args_doc} is @code{"FOO BAR\n-x BLAH"}, and the -@samp{-x} option's purpose is to distinguish these two cases, @samp{-x} -should probably be marked @code{OPTION_NO_USAGE}. -@end vtable - -@node Argp Parser Functions, Argp Children, Argp Option Vectors, Argp Parsers -@subsection Argp Parser Functions - -The function pointed to by the @code{parser} field in a @code{struct -argp} (@pxref{Argp Parsers}) defines what actions take place in response -to each option or argument parsed. It is also used as a hook, allowing a -parser to perform tasks at certain other points during parsing. - -@need 2000 -Argp parser functions have the following type signature: - -@cindex argp parser functions -@smallexample -error_t @var{parser} (int @var{key}, char *@var{arg}, struct argp_state *@var{state}) -@end smallexample - -@noindent -where the arguments are as follows: - -@table @var -@item key -For each option that is parsed, @var{parser} is called with a value of -@var{key} from that option's @code{key} field in the option -vector. @xref{Argp Option Vectors}. @var{parser} is also called at -other times with special reserved keys, such as @code{ARGP_KEY_ARG} for -non-option arguments. @xref{Argp Special Keys}. - -@item arg -If @var{key} is an option, @var{arg} is its given value. This defaults -to zero if no value is specified. Only options that have a non-zero -@code{arg} field can ever have a value. These must @emph{always} have a -value unless the @code{OPTION_ARG_OPTIONAL} flag is specified. If the -input being parsed specifies a value for an option that doesn't allow -one, an error results before @var{parser} ever gets called. - -If @var{key} is @code{ARGP_KEY_ARG}, @var{arg} is a non-option -argument. Other special keys always have a zero @var{arg}. - -@item state -@var{state} points to a @code{struct argp_state}, containing useful -information about the current parsing state for use by -@var{parser}. @xref{Argp Parsing State}. -@end table - -When @var{parser} is called, it should perform whatever action is -appropriate for @var{key}, and return @code{0} for success, -@code{ARGP_ERR_UNKNOWN} if the value of @var{key} is not handled by this -parser function, or a unix error code if a real error -occurred. @xref{Error Codes}. - -@comment argp.h -@comment GNU -@deftypevr Macro int ARGP_ERR_UNKNOWN -Argp parser functions should return @code{ARGP_ERR_UNKNOWN} for any -@var{key} value they do not recognize, or for non-option arguments -(@code{@var{key} == ARGP_KEY_ARG}) that they are not equipped to handle. -@end deftypevr - -@need 3000 -A typical parser function uses a switch statement on @var{key}: - -@smallexample -error_t -parse_opt (int key, char *arg, struct argp_state *state) -@{ - switch (key) - @{ - case @var{option_key}: - @var{action} - break; - @dots{} - default: - return ARGP_ERR_UNKNOWN; - @} - return 0; -@} -@end smallexample - -@menu -* Keys: Argp Special Keys. Special values for the @var{key} argument. -* State: Argp Parsing State. What the @var{state} argument refers to. -* Functions: Argp Helper Functions. Functions to help during argp parsing. -@end menu - -@node Argp Special Keys, Argp Parsing State, , Argp Parser Functions -@subsubsection Special Keys for Argp Parser Functions - -In addition to key values corresponding to user options, the @var{key} -argument to argp parser functions may have a number of other special -values. In the following example @var{arg} and @var{state} refer to -parser function arguments. @xref{Argp Parser Functions}. - -@vtable @code -@comment argp.h -@comment GNU -@item ARGP_KEY_ARG -This is not an option at all, but rather a command line argument, whose -value is pointed to by @var{arg}. - -When there are multiple parser functions in play due to argp parsers -being combined, it's impossible to know which one will handle a specific -argument. Each is called until one returns 0 or an error other than -@code{ARGP_ERR_UNKNOWN}; if an argument is not handled, -@code{argp_parse} immediately returns success, without parsing any more -arguments. - -Once a parser function returns success for this key, that fact is -recorded, and the @code{ARGP_KEY_NO_ARGS} case won't be -used. @emph{However}, if while processing the argument a parser function -decrements the @code{next} field of its @var{state} argument, the option -won't be considered processed; this is to allow you to actually modify -the argument, perhaps into an option, and have it processed again. - -@comment argp.h -@comment GNU -@item ARGP_KEY_ARGS -If a parser function returns @code{ARGP_ERR_UNKNOWN} for -@code{ARGP_KEY_ARG}, it is immediately called again with the key -@code{ARGP_KEY_ARGS}, which has a similar meaning, but is slightly more -convenient for consuming all remaining arguments. @var{arg} is 0, and -the tail of the argument vector may be found at @code{@var{state}->argv -+ @var{state}->next}. If success is returned for this key, and -@code{@var{state}->next} is unchanged, all remaining arguments are -considered to have been consumed. Otherwise, the amount by which -@code{@var{state}->next} has been adjusted indicates how many were used. -Here's an example that uses both, for different args: - - -@smallexample -@dots{} -case ARGP_KEY_ARG: - if (@var{state}->arg_num == 0) - /* First argument */ - first_arg = @var{arg}; - else - /* Let the next case parse it. */ - return ARGP_KEY_UNKNOWN; - break; -case ARGP_KEY_ARGS: - remaining_args = @var{state}->argv + @var{state}->next; - num_remaining_args = @var{state}->argc - @var{state}->next; - break; -@end smallexample - -@comment argp.h -@comment GNU -@item ARGP_KEY_END -This indicates that there are no more command line arguments. Parser -functions are called in a different order, children first. This allows -each parser to clean up its state for the parent. - -@comment argp.h -@comment GNU -@item ARGP_KEY_NO_ARGS -Because it's common to do some special processing if there aren't any -non-option args, parser functions are called with this key if they -didn't successfully process any non-option arguments. This is called -just before @code{ARGP_KEY_END}, where more general validity checks on -previously parsed arguments take place. - -@comment argp.h -@comment GNU -@item ARGP_KEY_INIT -This is passed in before any parsing is done. Afterwards, the values of -each element of the @code{child_input} field of @var{state}, if any, are -copied to each child's state to be the initial value of the @code{input} -when @emph{their} parsers are called. - -@comment argp.h -@comment GNU -@item ARGP_KEY_SUCCESS -Passed in when parsing has successfully been completed, even if -arguments remain. - -@comment argp.h -@comment GNU -@item ARGP_KEY_ERROR -Passed in if an error has occurred and parsing is terminated. In this -case a call with a key of @code{ARGP_KEY_SUCCESS} is never made. - -@comment argp.h -@comment GNU -@item ARGP_KEY_FINI -The final key ever seen by any parser, even after -@code{ARGP_KEY_SUCCESS} and @code{ARGP_KEY_ERROR}. Any resources -allocated by @code{ARGP_KEY_INIT} may be freed here. At times, certain -resources allocated are to be returned to the caller after a successful -parse. In that case, those particular resources can be freed in the -@code{ARGP_KEY_ERROR} case. -@end vtable - -In all cases, @code{ARGP_KEY_INIT} is the first key seen by parser -functions, and @code{ARGP_KEY_FINI} the last, unless an error was -returned by the parser for @code{ARGP_KEY_INIT}. Other keys can occur -in one the following orders. @var{opt} refers to an arbitrary option -key: - -@table @asis -@item @var{opt}@dots{} @code{ARGP_KEY_NO_ARGS} @code{ARGP_KEY_END} @code{ARGP_KEY_SUCCESS} -The arguments being parsed did not contain any non-option arguments. - -@item ( @var{opt} | @code{ARGP_KEY_ARG} )@dots{} @code{ARGP_KEY_END} @code{ARGP_KEY_SUCCESS} -All non-option arguments were successfully handled by a parser -function. There may be multiple parser functions if multiple argp -parsers were combined. - -@item ( @var{opt} | @code{ARGP_KEY_ARG} )@dots{} @code{ARGP_KEY_SUCCESS} -Some non-option argument went unrecognized. - -This occurs when every parser function returns @code{ARGP_KEY_UNKNOWN} -for an argument, in which case parsing stops at that argument if -@var{arg_index} is a null pointer. Otherwise an error occurs. -@end table - -In all cases, if a non-null value for @var{arg_index} gets passed to -@code{argp_parse}, the index of the first unparsed command-line argument -is passed back in that value. - -If an error occurs and is either detected by argp or because a parser -function returned an error value, each parser is called with -@code{ARGP_KEY_ERROR}. No further calls are made, except the final call -with @code{ARGP_KEY_FINI}. - -@node Argp Parsing State, Argp Helper Functions, Argp Special Keys, Argp Parser Functions -@subsubsection Argp Parsing State - -The third argument to argp parser functions (@pxref{Argp Parser -Functions}) is a pointer to a @code{struct argp_state}, which contains -information about the state of the option parsing. - -@comment argp.h -@comment GNU -@deftp {Data Type} {struct argp_state} -This structure has the following fields, which may be modified as noted: - -@table @code -@item const struct argp *const root_argp -The top level argp parser being parsed. Note that this is often -@emph{not} the same @code{struct argp} passed into @code{argp_parse} by -the invoking program. @xref{Argp}. It is an internal argp parser that -contains options implemented by @code{argp_parse} itself, such as -@samp{--help}. - -@item int argc -@itemx char **argv -The argument vector being parsed. This may be modified. - -@item int next -The index in @code{argv} of the next argument to be parsed. This may be -modified. - -One way to consume all remaining arguments in the input is to set -@code{@var{state}->next = @var{state}->argc}, perhaps after recording -the value of the @code{next} field to find the consumed arguments. The -current option can be re-parsed immediately by decrementing this field, -then modifying @code{@var{state}->argv[@var{state}->next]} to reflect -the option that should be reexamined. - -@item unsigned flags -The flags supplied to @code{argp_parse}. These may be modified, although -some flags may only take effect when @code{argp_parse} is first -invoked. @xref{Argp Flags}. - -@item unsigned arg_num -While calling a parsing function with the @var{key} argument -@code{ARGP_KEY_ARG}, this represents the number of the current arg, -starting at 0. It is incremented after each @code{ARGP_KEY_ARG} call -returns. At all other times, this is the number of @code{ARGP_KEY_ARG} -arguments that have been processed. - -@item int quoted -If non-zero, the index in @code{argv} of the first argument following a -special @samp{--} argument. This prevents anything that follows from -being interpreted as an option. It is only set after argument parsing -has proceeded past this point. - -@item void *input -An arbitrary pointer passed in from the caller of @code{argp_parse}, in -the @var{input} argument. - -@item void **child_inputs -These are values that will be passed to child parsers. This vector will -be the same length as the number of children in the current parser. Each -child parser will be given the value of -@code{@var{state}->child_inputs[@var{i}]} as @emph{its} -@code{@var{state}->input} field, where @var{i} is the index of the child -in the this parser's @code{children} field. @xref{Argp Children}. - -@item void *hook -For the parser function's use. Initialized to 0, but otherwise ignored -by argp. - -@item char *name -The name used when printing messages. This is initialized to -@code{argv[0]}, or @code{program_invocation_name} if @code{argv[0]} is -unavailable. - -@item FILE *err_stream -@itemx FILE *out_stream -The stdio streams used when argp prints. Error messages are printed to -@code{err_stream}, all other output, such as @samp{--help} output) to -@code{out_stream}. These are initialized to @code{stderr} and -@code{stdout} respectively. @xref{Standard Streams}. - -@item void *pstate -Private, for use by the argp implementation. -@end table -@end deftp - -@node Argp Helper Functions, , Argp Parsing State, Argp Parser Functions -@subsubsection Functions For Use in Argp Parsers - -Argp provides a number of functions available to the user of argp -(@pxref{Argp Parser Functions}), mostly for producing error messages. -These take as their first argument the @var{state} argument to the -parser function. @xref{Argp Parsing State}. - - -@cindex usage messages, in argp -@comment argp.h -@comment GNU -@deftypefun void argp_usage (const struct argp_state *@var{state}) -@safety{@prelim{}@mtunsafe{@mtasurace{:argpbuf} @mtsenv{} @mtslocale{}}@asunsafe{@ascuheap{} @ascuintl{} @asucorrupt{}}@acunsafe{@acsmem{} @acucorrupt{} @aculock{}}} -@c Just calls argp_state_help with stderr and ARGP_HELP_STD_USAGE. -Outputs the standard usage message for the argp parser referred to by -@var{state} to @code{@var{state}->err_stream} and terminates the program -with @code{exit (argp_err_exit_status)}. @xref{Argp Global Variables}. -@end deftypefun - -@cindex syntax error messages, in argp -@comment argp.h -@comment GNU -@deftypefun void argp_error (const struct argp_state *@var{state}, const char *@var{fmt}, @dots{}) -@safety{@prelim{}@mtunsafe{@mtasurace{:argpbuf} @mtsenv{} @mtslocale{}}@asunsafe{@ascuheap{} @ascuintl{} @asucorrupt{}}@acunsafe{@acsmem{} @acucorrupt{} @aculock{}}} -@c Lock stream, vasprintf the formatted message into a buffer, print the -@c buffer prefixed by the short program name (in libc, -@c argp_short_program_name is a macro that expands to -@c program_invocation_short_name), releases the buffer, then call -@c argp_state_help with stream and ARGP_HELP_STD_ERR, unlocking the -@c stream at the end. -Prints the printf format string @var{fmt} and following args, preceded -by the program name and @samp{:}, and followed by a @w{@samp{Try @dots{} ---help}} message, and terminates the program with an exit status of -@code{argp_err_exit_status}. @xref{Argp Global Variables}. -@end deftypefun - -@cindex error messages, in argp -@comment argp.h -@comment GNU -@deftypefun void argp_failure (const struct argp_state *@var{state}, int @var{status}, int @var{errnum}, const char *@var{fmt}, @dots{}) -@safety{@prelim{}@mtsafe{}@asunsafe{@asucorrupt{} @ascuheap{}}@acunsafe{@aculock{} @acucorrupt{} @acsmem{}}} -@c Lock stream, write out the short program name, vasprintf the optional -@c formatted message to a buffer, print the buffer prefixed by colon and -@c blank, release the buffer, call strerror_r with an automatic buffer, -@c print it out after colon and blank, put[w]c a line break, unlock the -@c stream, then exit unless ARGP_NO_EXIT. -Similar to the standard GNU error-reporting function @code{error}, this -prints the program name and @samp{:}, the printf format string -@var{fmt}, and the appropriate following args. If it is non-zero, the -standard unix error text for @var{errnum} is printed. If @var{status} is -non-zero, it terminates the program with that value as its exit status. - -The difference between @code{argp_failure} and @code{argp_error} is that -@code{argp_error} is for @emph{parsing errors}, whereas -@code{argp_failure} is for other problems that occur during parsing but -don't reflect a syntactic problem with the input, such as illegal values -for options, bad phase of the moon, etc. -@end deftypefun - -@comment argp.h -@comment GNU -@deftypefun void argp_state_help (const struct argp_state *@var{state}, FILE *@var{stream}, unsigned @var{flags}) -@safety{@prelim{}@mtunsafe{@mtasurace{:argpbuf} @mtsenv{} @mtslocale{}}@asunsafe{@ascuheap{} @ascuintl{} @asucorrupt{}}@acunsafe{@acsmem{} @acucorrupt{} @aculock{}}} -@c Just calls _help with the short program name and optionally exit. -@c The main problems in _help, besides the usual issues with stream I/O -@c and translation, are the use of a static buffer (uparams, thus -@c @mtasurace:argpbuf) that makes the whole thing thread-unsafe, reading -@c from the environment for ARGP_HELP_FMT, accessing the locale object -@c multiple times. - -@c _help @mtsenv @mtasurace:argpbuf @mtslocale @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock -@c dgettext @ascuintl -@c flockfile @aculock -@c funlockfile @aculock -@c fill_in_uparams @mtsenv @mtasurace:argpbuf @mtslocale @asucorrupt @ascuheap @aculock @acucorrupt @acsmem -@c argp_failure dup (status = errnum = 0) -@c atoi dup @mtslocale -@c argp_hol @ascuheap @acsmem -@c make_hol @ascuheap @acsmem -@c hol_add_cluster @ascuheap @acsmem -@c hol_append @ascuheap @acsmem -@c hol_set_group ok -@c hol_find_entry ok -@c hol_sort @mtslocale @acucorrupt -@c qsort dup @acucorrupt -@c hol_entry_qcmp @mtslocale -@c hol_entry_cmp @mtslocale -@c group_cmp ok -@c hol_cluster_cmp ok -@c group_cmp ok -@c hol_entry_first_short @mtslocale -@c hol_entry_short_iterate [@mtslocale] -@c until_short ok -@c oshort ok -@c isprint ok -@c odoc ok -@c hol_entry_first_long ok -@c canon_doc_option @mtslocale -@c tolower dup -@c hol_usage @mtslocale @ascuintl @ascuheap @acsmem -@c hol_entry_short_iterate ok -@c add_argless_short_opt ok -@c argp_fmtstream_printf dup -@c hol_entry_short_iterate @mtslocale @ascuintl @ascuheap @acsmem -@c usage_argful_short_opt @mtslocale @ascuintl @ascuheap @acsmem -@c dgettext dup -@c argp_fmtstream_printf dup -@c hol_entry_long_iterate @mtslocale @ascuintl @ascuheap @acsmem -@c usage_long_opt @mtslocale @ascuintl @ascuheap @acsmem -@c dgettext dup -@c argp_fmtstream_printf dup -@c hol_help @mtslocale @mtasurace:argpbuf @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock -@c hol_entry_help @mtslocale @mtasurace:argpbuf @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock -@c argp_fmtstream_set_lmargin dup -@c argp_fmtstream_wmargin dup -@c argp_fmtstream_set_wmargin dup -@c comma @mtslocale @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock -@c argp_fmtstream_putc dup -@c hol_cluster_is_child ok -@c argp_fmtstream_wmargin dup -@c print_header dup -@c argp_fmtstream_set_wmargin dup -@c argp_fmtstream_puts dup -@c indent_to dup -@c argp_fmtstream_putc dup -@c arg @mtslocale @ascuheap @acsmem -@c argp_fmtstream_printf dup -@c odoc dup -@c argp_fmtstream_puts dup -@c argp_fmtstream_printf dup -@c print_header @mtslocale @mtasurace:argpbuf @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock -@c dgettext dup -@c filter_doc dup -@c argp_fmtstream_putc dup -@c indent_to dup -@c argp_fmtstream_set_lmargin dup -@c argp_fmtstream_set_wmargin dup -@c argp_fmtstream_puts dup -@c free dup -@c filter_doc dup -@c argp_fmtstream_point dup -@c indent_to @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock -@c argp_fmtstream_point dup -@c argp_fmtstream_putc dup -@c dgettext dup -@c filter_doc dup -@c argp_fmtstream_putc dup -@c argp_fmtstream_puts dup -@c free dup -@c hol_free @ascuheap @acsmem -@c free dup -@c argp_args_levels ok -@c argp_args_usage @mtslocale @ascuintl @ascuheap @asucorrupt @acsmem @acucorrupt @aculock -@c dgettext dup -@c filter_doc ok -@c argp_input ok -@c argp->help_filter -@c space @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock -@c argp_fmtstream_point dup -@c argp_fmtstream_rmargin @mtslocale @asucorrupt @acucorrupt @aculock -@c argp_fmtstream_update dup -@c argp_fmtstream_putc dup -@c argp_fmtstream_write dup -@c free dup -@c argp_doc @mtslocale @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock -@c dgettext @ascuintl -@c strndup @ascuheap @acsmem -@c argp_input dup -@c argp->help_filter -@c argp_fmtstream_putc @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock -@c argp_fmtstream_ensure dup -@c argp_fmtstream_write dup -@c argp_fmtstream_puts dup -@c argp_fmtstream_point @mtslocale @asucorrupt @acucorrupt @aculock -@c argp_fmtstream_update dup -@c argp_fmtstream_lmargin dup -@c free dup -@c argp_make_fmtstream @ascuheap @acsmem -@c argp_fmtstream_free @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock -@c argp_fmtstream_update @mtslocale @asucorrupt @acucorrupt @aculock -@c put[w]c_unlocked dup -@c isblank in loop @mtslocale -@c fxprintf @aculock -@c fxprintf @aculock -@c free dup -@c argp_fmtstream_set_wmargin @mtslocale @asucorrupt @acucorrupt @aculock -@c argp_fmtstream_update dup -@c argp_fmtstream_printf @mtslocale @ascuheap @acsmem -@c argp_fmtstream_ensure dup -@c vsnprintf dup -@c argp_fmtstream_set_lmargin @mtslocale @asucorrupt @acucorrupt @aculock -@c argp_fmtstream_update dup -@c argp_fmtstream_puts @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock -@c argp_fmtstream_write @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock -@c argp_fmtstream_ensure @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock -@c argp_fmtstream_update dup -@c fxprintf @aculock -@c realloc @ascuheap @acsmem -Outputs a help message for the argp parser referred to by @var{state}, -to @var{stream}. The @var{flags} argument determines what sort of help -message is produced. @xref{Argp Help Flags}. -@end deftypefun - -Error output is sent to @code{@var{state}->err_stream}, and the program -name printed is @code{@var{state}->name}. - -The output or program termination behavior of these functions may be -suppressed if the @code{ARGP_NO_EXIT} or @code{ARGP_NO_ERRS} flags are -passed to @code{argp_parse}. @xref{Argp Flags}. - -This behavior is useful if an argp parser is exported for use by other -programs (e.g., by a library), and may be used in a context where it is -not desirable to terminate the program in response to parsing errors. In -argp parsers intended for such general use, and for the case where the -program @emph{doesn't} terminate, calls to any of these functions should -be followed by code that returns the appropriate error code: - -@smallexample -if (@var{bad argument syntax}) - @{ - argp_usage (@var{state}); - return EINVAL; - @} -@end smallexample - -@noindent -If a parser function will @emph{only} be used when @code{ARGP_NO_EXIT} -is not set, the return may be omitted. - -@node Argp Children, Argp Help Filtering, Argp Parser Functions, Argp Parsers -@subsection Combining Multiple Argp Parsers - -The @code{children} field in a @code{struct argp} enables other argp -parsers to be combined with the referencing one for the parsing of a -single set of arguments. This field should point to a vector of -@code{struct argp_child}, which is terminated by an entry having a value -of zero in the @code{argp} field. - -Where conflicts between combined parsers arise, as when two specify an -option with the same name, the parser conflicts are resolved in favor of -the parent argp parser(s), or the earlier of the argp parsers in the -list of children. - -@comment argp.h -@comment GNU -@deftp {Data Type} {struct argp_child} -An entry in the list of subsidiary argp parsers pointed to by the -@code{children} field in a @code{struct argp}. The fields are as -follows: - -@table @code -@item const struct argp *argp -The child argp parser, or zero to end of the list. - -@item int flags -Flags for this child. - -@item const char *header -If non-zero, this is an optional header to be printed within help output -before the child options. As a side-effect, a non-zero value forces the -child options to be grouped together. To achieve this effect without -actually printing a header string, use a value of @code{""}. As with -header strings specified in an option entry, the conventional value of -the last character is @samp{:}. @xref{Argp Option Vectors}. - -@item int group -This is where the child options are grouped relative to the other -`consolidated' options in the parent argp parser. The values are the -same as the @code{group} field in @code{struct argp_option}. @xref{Argp -Option Vectors}. All child-groupings follow parent options at a -particular group level. If both this field and @code{header} are zero, -then the child's options aren't grouped together, they are merged with -parent options at the parent option group level. - -@end table -@end deftp - -@node Argp Flags, Argp Help, Argp Parsers, Argp -@subsection Flags for @code{argp_parse} - -The default behavior of @code{argp_parse} is designed to be convenient -for the most common case of parsing program command line argument. To -modify these defaults, the following flags may be or'd together in the -@var{flags} argument to @code{argp_parse}: - -@vtable @code -@comment argp.h -@comment GNU -@item ARGP_PARSE_ARGV0 -Don't ignore the first element of the @var{argv} argument to -@code{argp_parse}. Unless @code{ARGP_NO_ERRS} is set, the first element -of the argument vector is skipped for option parsing purposes, as it -corresponds to the program name in a command line. - -@comment argp.h -@comment GNU -@item ARGP_NO_ERRS -Don't print error messages for unknown options to @code{stderr}; unless -this flag is set, @code{ARGP_PARSE_ARGV0} is ignored, as @code{argv[0]} -is used as the program name in the error messages. This flag implies -@code{ARGP_NO_EXIT}. This is based on the assumption that silent exiting -upon errors is bad behavior. - -@comment argp.h -@comment GNU -@item ARGP_NO_ARGS -Don't parse any non-option args. Normally these are parsed by calling -the parse functions with a key of @code{ARGP_KEY_ARG}, the actual -argument being the value. This flag needn't normally be set, as the -default behavior is to stop parsing as soon as an argument fails to be -parsed. @xref{Argp Parser Functions}. - -@comment argp.h -@comment GNU -@item ARGP_IN_ORDER -Parse options and arguments in the same order they occur on the command -line. Normally they're rearranged so that all options come first. - -@comment argp.h -@comment GNU -@item ARGP_NO_HELP -Don't provide the standard long option @samp{--help}, which ordinarily -causes usage and option help information to be output to @code{stdout} -and @code{exit (0)}. - -@comment argp.h -@comment GNU -@item ARGP_NO_EXIT -Don't exit on errors, although they may still result in error messages. - -@comment argp.h -@comment GNU -@item ARGP_LONG_ONLY -Use the GNU getopt `long-only' rules for parsing arguments. This allows -long-options to be recognized with only a single @samp{-} -(i.e., @samp{-help}). This results in a less useful interface, and its -use is discouraged as it conflicts with the way most GNU programs work -as well as the GNU coding standards. - -@comment argp.h -@comment GNU -@item ARGP_SILENT -Turns off any message-printing/exiting options, specifically -@code{ARGP_NO_EXIT}, @code{ARGP_NO_ERRS}, and @code{ARGP_NO_HELP}. -@end vtable - -@node Argp Help Filtering, , Argp Children, Argp Parsers -@need 2000 -@subsection Customizing Argp Help Output - -The @code{help_filter} field in a @code{struct argp} is a pointer to a -function that filters the text of help messages before displaying -them. They have a function signature like: - -@smallexample -char *@var{help-filter} (int @var{key}, const char *@var{text}, void *@var{input}) -@end smallexample - - -@noindent -Where @var{key} is either a key from an option, in which case @var{text} -is that option's help text. @xref{Argp Option Vectors}. Alternately, one -of the special keys with names beginning with @samp{ARGP_KEY_HELP_} -might be used, describing which other help text @var{text} will contain. -@xref{Argp Help Filter Keys}. - -The function should return either @var{text} if it remains as-is, or a -replacement string allocated using @code{malloc}. This will be either be -freed by argp or zero, which prints nothing. The value of @var{text} is -supplied @emph{after} any translation has been done, so if any of the -replacement text needs translation, it will be done by the filter -function. @var{input} is either the input supplied to @code{argp_parse} -or it is zero, if @code{argp_help} was called directly by the user. - -@menu -* Keys: Argp Help Filter Keys. Special @var{key} values for help filter functions. -@end menu - -@node Argp Help Filter Keys, , , Argp Help Filtering -@subsubsection Special Keys for Argp Help Filter Functions - -The following special values may be passed to an argp help filter -function as the first argument in addition to key values for user -options. They specify which help text the @var{text} argument contains: - -@vtable @code -@comment argp.h -@comment GNU -@item ARGP_KEY_HELP_PRE_DOC -The help text preceding options. - -@comment argp.h -@comment GNU -@item ARGP_KEY_HELP_POST_DOC -The help text following options. - -@comment argp.h -@comment GNU -@item ARGP_KEY_HELP_HEADER -The option header string. - -@comment argp.h -@comment GNU -@item ARGP_KEY_HELP_EXTRA -This is used after all other documentation; @var{text} is zero for this key. - -@comment argp.h -@comment GNU -@item ARGP_KEY_HELP_DUP_ARGS_NOTE -The explanatory note printed when duplicate option arguments have been suppressed. - -@comment argp.h -@comment GNU -@item ARGP_KEY_HELP_ARGS_DOC -The argument doc string; formally the @code{args_doc} field from the argp parser. @xref{Argp Parsers}. -@end vtable - -@node Argp Help, Argp Examples, Argp Flags, Argp -@subsection The @code{argp_help} Function - -Normally programs using argp need not be written with particular -printing argument-usage-type help messages in mind as the standard -@samp{--help} option is handled automatically by argp. Typical error -cases can be handled using @code{argp_usage} and -@code{argp_error}. @xref{Argp Helper Functions}. However, if it's -desirable to print a help message in some context other than parsing the -program options, argp offers the @code{argp_help} interface. - -@comment argp.h -@comment GNU -@deftypefun void argp_help (const struct argp *@var{argp}, FILE *@var{stream}, unsigned @var{flags}, char *@var{name}) -@safety{@prelim{}@mtunsafe{@mtasurace{:argpbuf} @mtsenv{} @mtslocale{}}@asunsafe{@ascuheap{} @ascuintl{} @asucorrupt{}}@acunsafe{@acsmem{} @acucorrupt{} @aculock{}}} -@c Just calls _help. -This outputs a help message for the argp parser @var{argp} to -@var{stream}. The type of messages printed will be determined by -@var{flags}. - -Any options such as @samp{--help} that are implemented automatically by -argp itself will @emph{not} be present in the help output; for this -reason it is best to use @code{argp_state_help} if calling from within -an argp parser function. @xref{Argp Helper Functions}. -@end deftypefun - -@menu -* Flags: Argp Help Flags. Specifying what sort of help message to print. -@end menu - -@node Argp Help Flags, , , Argp Help -@subsection Flags for the @code{argp_help} Function - -When calling @code{argp_help} (@pxref{Argp Help}) or -@code{argp_state_help} (@pxref{Argp Helper Functions}) the exact output -is determined by the @var{flags} argument. This should consist of any of -the following flags, or'd together: - -@vtable @code -@item ARGP_HELP_USAGE -A unix @samp{Usage:} message that explicitly lists all options. - -@item ARGP_HELP_SHORT_USAGE -A unix @samp{Usage:} message that displays an appropriate placeholder to -indicate where the options go; useful for showing the non-option -argument syntax. - -@item ARGP_HELP_SEE -A @samp{Try @dots{} for more help} message; @samp{@dots{}} contains the -program name and @samp{--help}. - -@item ARGP_HELP_LONG -A verbose option help message that gives each option available along -with its documentation string. - -@item ARGP_HELP_PRE_DOC -The part of the argp parser doc string preceding the verbose option help. - -@item ARGP_HELP_POST_DOC -The part of the argp parser doc string that following the verbose option help. - -@item ARGP_HELP_DOC -@code{(ARGP_HELP_PRE_DOC | ARGP_HELP_POST_DOC)} - -@item ARGP_HELP_BUG_ADDR -A message that prints where to report bugs for this program, if the -@code{argp_program_bug_address} variable contains this information. - -@item ARGP_HELP_LONG_ONLY -This will modify any output to reflect the @code{ARGP_LONG_ONLY} mode. -@end vtable - -The following flags are only understood when used with -@code{argp_state_help}. They control whether the function returns after -printing its output, or terminates the program: - -@vtable @code -@item ARGP_HELP_EXIT_ERR -This will terminate the program with @code{exit (argp_err_exit_status)}. - -@item ARGP_HELP_EXIT_OK -This will terminate the program with @code{exit (0)}. -@end vtable - -The following flags are combinations of the basic flags for printing -standard messages: - -@vtable @code -@item 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. - -@item 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. - -@item ARGP_HELP_STD_HELP -This prints the standard response for a @samp{--help} option, and -terminates the program successfully. -@end vtable - -@node Argp Examples, Argp User Customization, Argp Help, Argp -@subsection Argp Examples - -These example programs demonstrate the basic usage of argp. - -@menu -* 1: Argp Example 1. A minimal program using argp. -* 2: Argp Example 2. A program using only default options. -* 3: Argp Example 3. A simple program with user options. -* 4: Argp Example 4. Combining multiple argp parsers. -@end menu - -@node Argp Example 1, Argp Example 2, , Argp Examples -@subsubsection A Minimal Program Using Argp - -This is perhaps the smallest program possible that uses argp. It won't -do much except give an error message and exit when there are any -arguments, and prints a rather pointless message for @samp{--help}. - -@smallexample -@include argp-ex1.c.texi -@end smallexample - -@node Argp Example 2, Argp Example 3, Argp Example 1, Argp Examples -@subsubsection A Program Using Argp with Only Default Options - -This program doesn't use any options or arguments, it uses argp to be -compliant with the GNU standard command line format. - -In addition to giving no arguments and implementing a @samp{--help} -option, this example has a @samp{--version} option, which will put the -given documentation string and bug address in the @samp{--help} output, -as per GNU standards. - -The variable @code{argp} contains the argument parser -specification. Adding fields to this structure is the way most -parameters are passed to @code{argp_parse}. The first three fields are -normally used, but they are not in this small program. There are also -two global variables that argp can use defined here, -@code{argp_program_version} and @code{argp_program_bug_address}. They -are considered global variables because they will almost always be -constant for a given program, even if they use different argument -parsers for various tasks. - -@smallexample -@include argp-ex2.c.texi -@end smallexample - -@node Argp Example 3, Argp Example 4, Argp Example 2, Argp Examples -@subsubsection A Program Using Argp with User Options - -This program uses the same features as example 2, adding user options -and arguments. - -We now use the first four fields in @code{argp} (@pxref{Argp Parsers}) -and specify @code{parse_opt} as the parser function. @xref{Argp Parser -Functions}. - -Note that in this example, @code{main} uses a structure to communicate -with the @code{parse_opt} function, a pointer to which it passes in the -@code{input} argument to @code{argp_parse}. @xref{Argp}. It is retrieved -by @code{parse_opt} through the @code{input} field in its @code{state} -argument. @xref{Argp Parsing State}. Of course, it's also possible to -use global variables instead, but using a structure like this is -somewhat more flexible and clean. - -@smallexample -@include argp-ex3.c.texi -@end smallexample - -@node Argp Example 4, , Argp Example 3, Argp Examples -@subsubsection A Program Using Multiple Combined Argp Parsers - -This program uses the same features as example 3, but has more options, -and presents more structure in the @samp{--help} output. It also -illustrates how you can `steal' the remainder of the input arguments -past a certain point for programs that accept a list of items. It also -illustrates the @var{key} value @code{ARGP_KEY_NO_ARGS}, which is only -given if no non-option arguments were supplied to the -program. @xref{Argp Special Keys}. - -For structuring help output, two features are used: @emph{headers} and a -two part option string. The @emph{headers} are entries in the options -vector. @xref{Argp Option Vectors}. The first four fields are zero. The -two part documentation string are in the variable @code{doc}, which -allows documentation both before and after the options. @xref{Argp -Parsers}, the two parts of @code{doc} are separated by a vertical-tab -character (@code{'\v'}, or @code{'\013'}). By convention, the -documentation before the options is a short string stating what the -program does, and after any options it is longer, describing the -behavior in more detail. All documentation strings are automatically -filled for output, although newlines may be included to force a line -break at a particular point. In addition, documentation strings are -passed to the @code{gettext} function, for possible translation into the -current locale. - -@smallexample -@include argp-ex4.c.texi -@end smallexample - -@node Argp User Customization, , Argp Examples, Argp -@subsection Argp User Customization - -@cindex ARGP_HELP_FMT environment variable -The formatting of argp @samp{--help} output may be controlled to some -extent by a program's users, by setting the @code{ARGP_HELP_FMT} -environment variable to a comma-separated list of tokens. Whitespace is -ignored: - -@table @samp -@item dup-args -@itemx no-dup-args -These turn @dfn{duplicate-argument-mode} on or off. In duplicate -argument mode, if an option that accepts an argument has multiple names, -the argument is shown for each name. Otherwise, it is only shown for the -first long option. A note is subsequently printed so the user knows that -it applies to other names as well. The default is @samp{no-dup-args}, -which is less consistent, but prettier. - -@item dup-args-note -@item no-dup-args-note -These will enable or disable the note informing the user of suppressed -option argument duplication. The default is @samp{dup-args-note}. - -@item short-opt-col=@var{n} -This prints the first short option in column @var{n}. The default is 2. - -@item long-opt-col=@var{n} -This prints the first long option in column @var{n}. The default is 6. - -@item doc-opt-col=@var{n} -This prints `documentation options' (@pxref{Argp Option Flags}) in -column @var{n}. The default is 2. - -@item opt-doc-col=@var{n} -This prints the documentation for options starting in column -@var{n}. The default is 29. - -@item header-col=@var{n} -This will indent the group headers that document groups of options to -column @var{n}. The default is 1. - -@item usage-indent=@var{n} -This will indent continuation lines in @samp{Usage:} messages to column -@var{n}. The default is 12. - -@item rmargin=@var{n} -This will word wrap help output at or before column @var{n}. The default -is 79. -@end table |