Merge branch '170622' of github.com:jwpi/util-linux

* '170622' of github.com:jwpi/util-linux:
  Docs: move option naming to howto-contribute.txt
  Docs: update howto-usage-function.txt
  Docs: add a comment for constants to boilerplate.c
  include/c.h: add USAGE_COMMANDS and USAGE_COLUMNS
This commit is contained in:
Karel Zak 2017-06-26 13:56:45 +02:00
commit d6ec64e824
11 changed files with 78 additions and 80 deletions

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@ -29,6 +29,11 @@
#include "closestream.h"
#include "nls.h"
/*
* FIXME: remove this comment.
* Other usage() constants that are not demonstrated below:
* USAGE_FUNCTIONS USAGE_COMMANDS USAGE_COLUMNS
*/
static void __attribute__((__noreturn__)) usage(FILE *out)
{
fputs(USAGE_HEADER, out);
@ -37,9 +42,6 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
fputs(USAGE_SEPARATOR, out);
fputs(_("Short program description.\n"), out);
fputs(USAGE_FUNCTIONS, out);
fputs(_(" -s, --do-something some specific task\n"), out);
fputs(_(" -o, --do-other some different task\n"), out);
fputs(USAGE_OPTIONS, out);
fputs(_(" -n, --no-argument option does not use argument\n"), out);
fputs(_(" --optional[=<arg>] option argument is optional\n"), out);

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@ -3,6 +3,7 @@ CONTENTS
Patching Process
Email Format
Coding Style
Options
Various Notes
Standards Compliance
@ -155,6 +156,30 @@ Coding Style
multiple lines. In case the shorthand does not look good on one line
use the normal "if () else" syntax.
Options
* The rule of thumb for options is that once they exist, you may not
change them, nor change how they work, nor remove them.
* The following options are well-known, and should not be used for any
other purpose:
-h, --help display usage and exit
-V, --version display version and exit
* Some commands use peculiar options and arguments. These will continue
to be supported, but anything like them will not be accepted as new
additions. A short list of examples:
Characters other than '-' to start an option. See '+' in 'more'.
Using a number as an option. See '-<number>' in 'more'.
Long options that start with a single '-'. See 'setterm'.
'-?' is not a synonym for '--help', but is an unknown option
resulting in a suggestion to try --help due to a getopt failure.
Various Notes
* util-linux does not use kernel headers for file system super

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@ -1,34 +1,29 @@
Well-known options
------------------
The following options are well-known, and should not be used for any
other purpose:
Example file
------------
-h, --help display usage and exit
-V, --version display version and exit
The rule of thumb with other options is that once they exist, you may
not change them, nor change how they work, nor remove them.
See Legacy options below.
Refer to the ./boilerplate.c example file while reading this howto.
How a usage text is supposed to look
------------------------------------
The usage output begins with an empty line, followed by 'Usage:', and
then the synopsis on the line after that. The synopsis and option-
description lines are all indented by one space (0x40).
The usage() output format is: Usage section, command description one-liner,
Options section (see below), special sections like 'Available columns', and
the last line is either the man page reference or and empty line. The output
begins with, and each of the above are separated by, one empty line.
The synopsis line describes how to compose the command. Sometimes you
may need multiple synopsis lines -- this is documented separately in the
Synopsis section.
The Usage section contains the synopsis line that describes how to compose
the command. Sometimes you may need multiple synopsis lines (see below).
Notations. Diamond brackets are used to mark an argument to be filled in.
Square brackets are used to mark anything that is optional, such as optional
command arguments, or optional option arguments. In the later case the '='
character is needed in front of the option argument, because one has to use
it. Three consecutive dots mean the unlimited repetition of the preceding.
Only the synopsis and option lines are indented. Indent is one space (0x40).
Option lines do not use line-ending punctuation. Other sentences do.
Notations: diamond brackets are used to mark an argument to be filled in;
square brackets are used to mark anything that is optional, such as optional
command arguments, or optional option arguments. In the later case the '='
character is required in between the option and argument with no whitespace;
three consecutive dots means the unlimited repetition of the preceding.
The short option is always written first, followed by the long option. They
are separated with a comma and one space. Lonely short or long options do
@ -63,22 +58,21 @@ Options:
For more details see program(1).
-- snip
Note that there are usage-function definitions in the 'c.h' include file
which you must use. The location of an example file is mentioned at the
end of this text.
Option descriptions
-------------------
This information also applies to other option-like arguments. That is,
arguments starting with '-'. Such as: functions, commands, and so forth.
An option description should not exceed the width of 80 characters. If
you need a longer description, use multiple lines and indentation.
The description text begins from the point of the longest option plus two
spaces. In case adding a new option would necessitate a re-indentation of
the descriptions, it either has to be done, or the new option should begin
its description on the next line. Usually the later is better. The --help
and --version options do not follow this rule, since they are defined as
spaces. If adding a new option would necessitate a re-indentation of the
descriptions, it either has to be done, or the new option should begin its
description on the next line. Usually the later is better. The --help and
--version options do not follow this rule, since they are defined as
constants to ease translation work.
An argument is preferably worded appropriately. For example, if an option
@ -87,10 +81,6 @@ expects a number as argument, '<num>' is a suitable argument indicator.
The order of the options has no special meaning, with the exception of
--help and --version which are expected to be last ones in the list.
The last line of the usage text is either empty, or a message informing
about the manual page. For example: 'For more details see example(1).'.
Between the options and the man-page message there is an empty line.
Usage function
--------------
@ -99,6 +89,10 @@ The standard usage() function takes either stderr or stdout as an argument.
The argument will determine whether the program will exit with an error or
with success. The usage() function will never return.
Section headers, man page, version, help, and other components of usage()
have string constants defined in 'include/c.h' which must be used. See the
example file listed at the top of this document.
In the code all the strings with options have to start at the same position.
See here what this means:
@ -114,17 +108,17 @@ no less. For example:
" or how is your klingon?\n"), out);
When existing usage output is changed, and it happens to be one big text,
split it into chunks the size of one option. The extra work this will
entail for translators will pay off later, at the time of the next change,
when they will not need to search in the long fuzzy text what was changed,
where, how, and whether it was the only change.
split it into chunks the size of one option. The extra work this will entail
for translators will pay off later; the next string change will not force a
search of the long fuzzy text for what was changed, where, how, and whether
it was the only change.
Synopsis
--------
You may need to use multiple synopsis lines to show that a command does
fundamentally different things depending on options and/or arguments.
fundamentally different things depending on the options and/or arguments.
For example, ionice either changes the priority of a running command, or
executes a program with a defined priority. Therefore it is reasonable
to have two synopsis lines:
@ -133,27 +127,8 @@ to have two synopsis lines:
ionice [options] <command> [<arg> ...]
Note that the synopsis is not meant to be a repetition of the options
segment. The fundamental difference in execution is a bit difficult to
define other than that usually the command author, package maintainer
or patch submitter will know when it should be done that way.
section. The fundamental difference in execution is a bit difficult to
define. The command author, package maintainer or patch submitter will
usually know when it should be done that way.
Legacy options
--------------
Some commands use peculiar options and arguments. These will continue
to be supported, but anything like them will not be accepted as new
additions. A short list of examples:
- Characters other than '-' to start an option. See '+' in 'more'.
- Using a number as an option. See '-<number>' in 'more'.
- Long options that start with a single '-'. See 'setterm'.
- '-?' is not expected to be a synonym of '--help', but is an unknown
option resulting in a suggestion to try --help due to a getopt failure.
Example file
------------
The file ./boilerplate.c is a minimal example of how to write
a usage function, set up option parsing, version printing and so on.

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@ -1850,7 +1850,7 @@ static void __attribute__ ((__noreturn__)) usage(FILE *out)
fputs(USAGE_SEPARATOR, out);
fputs(_("Display or manipulate a disk partition table.\n"), out);
fputs(_("\nCommands:\n"), out);
fputs(USAGE_COMMANDS, out);
fputs(_(" -A, --activate <dev> [<part> ...] list or set bootable MBR partitions\n"), out);
fputs(_(" -d, --dump <dev> dump partition table (usable for later input)\n"), out);
fputs(_(" -J, --json <dev> dump partition table in JSON format\n"), out);

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@ -307,11 +307,13 @@ static inline int xusleep(useconds_t usec)
/*
* Constant strings for usage() functions. For more info see
* Documentation/howto-usage-function.txt and disk-utils/delpart.c
* Documentation/{howto-usage-function.txt,boilerplate.c}
*/
#define USAGE_HEADER _("\nUsage:\n")
#define USAGE_OPTIONS _("\nOptions:\n")
#define USAGE_FUNCTIONS _("\nFunctions:\n")
#define USAGE_COMMANDS _("\nCommands:\n")
#define USAGE_COLUMNS _("\nAvailable columns:\n")
#define USAGE_SEPARATOR "\n"
#define USAGE_HELP _(" -h, --help display help information and exit\n")
#define USAGE_VERSION _(" -V, --version display version information and exit\n")

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@ -1255,11 +1255,9 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fprintf(out, _("\nAvailable columns:\n"));
fputs(USAGE_COLUMNS, out);
for (i = 0; i < ARRAY_SIZE(coldescs); i++)
fprintf(out, " %14s %s\n", coldescs[i].name,
_(coldescs[i].help));
fprintf(out, " %14s %s\n", coldescs[i].name, _(coldescs[i].help));
fprintf(out, USAGE_MAN_TAIL("lslogins(1)"));

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@ -1248,8 +1248,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fprintf(out, _("\nAvailable columns:\n"));
fputs(USAGE_COLUMNS, out);
for (i = 0; i < ARRAY_SIZE(infos); i++)
fprintf(out, " %11s %s\n", infos[i].name, _(infos[i].help));

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@ -300,7 +300,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
fputs(USAGE_SEPARATOR, out);
fputs(_("Run zone command on the given block device.\n"), out);
fputs(_("\nCommands:\n"), out);
fputs(USAGE_COMMANDS, out);
for (i = 0; i < ARRAY_SIZE(commands); i++)
fprintf(out, " %-11s %s\n", commands[i].name, _(commands[i].help));

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@ -2068,8 +2068,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fprintf(out, _("\nAvailable columns:\n"));
fputs(USAGE_COLUMNS, out);
for (i = 0; i < ARRAY_SIZE(coldescs); i++)
fprintf(out, " %13s %s\n", coldescs[i].name, _(coldescs[i].help));

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@ -388,10 +388,9 @@ static void __attribute__((__noreturn__)) lsmem_usage(FILE *out)
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fputs(_("\nAvailable columns:\n"), out);
fputs(USAGE_COLUMNS, out);
for (i = 0; i < ARRAY_SIZE(coldescs); i++)
fprintf(out, " %10s %s\n", coldescs[i].name, coldescs[i].help);
fprintf(out, " %10s %s\n", coldescs[i].name, _(coldescs[i].help));
fprintf(out, USAGE_MAN_TAIL("lsmem(1)"));

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@ -194,9 +194,8 @@ static void __attribute__ ((__noreturn__)) usage(FILE *out)
fputs(USAGE_SEPARATOR, out);
fprintf(out, _("The default device is %s.\n"), _PATH_WATCHDOG_DEV);
fputs(USAGE_SEPARATOR, out);
fputs(_("Available columns:\n"), out);
fputs(USAGE_COLUMNS, out);
for (i = 0; i < ARRAY_SIZE(infos); i++)
fprintf(out, " %13s %s\n", infos[i].name, _(infos[i].help));