@example
xgettext [@var{option}] [@var{inputfile}] @dots{}
@end example

The @code{xgettext} program extracts translatable strings from given
input files.

@subsection Input file location

@table @samp
@item @var{inputfile} @dots{}
Input files.

@item -f @var{file}
@itemx --files-from=@var{file}
Read the names of the input files from @var{file} instead of getting
them from the command line.

@item -D @var{directory}
@itemx --directory=@var{directory}
Add @var{directory} to the list of directories.  Source files are
searched relative to this list of directories.  The resulting @file{.po}
file will be written relative to the current directory, though.

@end table

If @var{inputfile} is @samp{-}, standard input is read.

@subsection Output file location

@table @samp
@item -d @var{name}
@itemx --default-domain=@var{name}
Use @file{@var{name}.po} for output (instead of @file{messages.po}).

@item -o @var{file}
@itemx --output=@var{file}
Write output to specified file (instead of @file{@var{name}.po} or
@file{messages.po}).

@item -p @var{dir}
@itemx --output-dir=@var{dir}
Output files will be placed in directory @var{dir}.

@end table

If the output @var{file} is @samp{-} or @samp{/dev/stdout}, the output
is written to standard output.

@subsection Choice of input file language

@table @samp
@item -L @var{name}
@itemx --language=@var{name}
Specifies the language of the input files.  The supported languages
are @code{C}, @code{C++}, @code{ObjectiveC}, @code{PO}, @code{Java},
@code{YCP}.

@item -C
@itemx --c++
This is a shorthand for @code{--language=C++}.

@end table

By default the language is guessed depending on the input file name
extension.

@subsection Operation mode

@table @samp
@item -j
@itemx --join-existing
Join messages with existing file.

@item -x @var{file}
@itemx --exclude-file=@var{file}
Entries from @var{file} are not extracted.  @var{file} should be a PO or
POT file.

@item -c [@var{tag}]
@itemx --add-comments[=@var{tag}]
Place comment block with @var{tag} (or those preceding keyword lines)
in output file.

@end table

@subsection Language=C/C++ specific options

@table @samp
@item -a
@itemx --extract-all
Extract all strings.

@item -k @var{keywordspec}
@itemx --keyword[=@var{keywordspec}]
Additional keyword to be looked for (without @var{keywordspec} means not to
use default keywords).

If @var{keywordspec} is a C identifer @var{id}, @code{xgettext} looks
for strings in the first argument of each call to the function or macro
@var{id}.  If @var{keywordspec} is of the form
@samp{@var{id}:@var{argnum}}, @code{xgettext} looks for strings in the
@var{argnum}th argument of the call.  If @var{keywordspec} is of the form
@samp{@var{id}:@var{argnum1},@var{argnum2}}, @code{xgettext} looks for
strings in the @var{argnum1}st argument and in the @var{argnum2}nd argument
of the call, and treats them as singular/plural variants for a message
with plural handling.

The default keyword specifications, which are always looked for if not
explicitly disabled, are @code{gettext}, @code{dgettext:2},
@code{dcgettext:2}, @code{ngettext:1,2}, @code{dngettext:2,3},
@code{dcngettext:2,3}, and @code{gettext_noop}.

@item -T
@itemx --trigraphs
Understand ANSI C trigraphs for input.

@itemx --debug
Use the flags @kbd{c-format} and @kbd{possible-c-format} to show who was
responsible for marking a message as a format string.  The latter form is
used if the @code{xgettext} program decided, the format form is used if
the programmer prescribed it.

By default only the @kbd{c-format} form is used.  The translator should
not have to care about these details.

@end table

This implementation of @code{xgettext} is able to process a few awkward
cases, like strings in preprocessor macros, ANSI concatenation of
adjacent strings, and escaped end of lines for continued strings.

@subsection Output details

@c --no-escape and --escape omitted on purpose.  They are not useful.

@table @samp
@item --force-po
Always write an output file even if no message is defined.

@item -i
@itemx --indent
Write the .po file using indented style.

@item --no-location
Do not write @samp{#: @var{filename}:@var{line}} lines.

@item -n
@itemx --add-location
Generate @samp{#: @var{filename}:@var{line}} lines (default).

@item --strict
Write out a strict Uniforum conforming PO file.  Note that this
Uniforum format should be avoided because it doesn't support the
GNU extensions.

@item -w @var{number}
@itemx --width=@var{number}
Set the output page width.  Long strings in the output files will be
split across multiple lines in order to ensure that each line's width
(= number of screen columns) is less or equal to the given @var{number}.

@item -s
@itemx --sort-output
Generate sorted output.  Note that using this option makes it much harder
for the translator to understand each message's context.

@item -F
@itemx --sort-by-file
Sort output by file location.

@item --omit-header
Don't write header with @samp{msgid ""} entry.

This is useful for testing purposes because it eliminates a source
of variance for generated @code{.gmo} files.  With @code{--omit-header},
two invocations of @code{xgettext} on the same files with the same
options at different times are guaranteed to produce the same results.

@item --foreign-user
Omit FSF copyright in output.  This can be useful for translators
outside the GNU project.

@item -m [@var{string}]
@itemx --msgstr-prefix[=@var{string}]
Use @var{string} (or "" if not specified) as prefix for msgstr entries.

@item -M [@var{string}]
@itemx --msgstr-suffix[=@var{string}]
Use @var{string} (or "" if not specified) as suffix for msgstr entries.

@end table

@subsection Informative output

@table @samp
@item -h
@itemx --help
Display this help and exit.

@item -V
@itemx --version
Output version information and exit.

@end table