Originální popis anglicky:
ctags - create a tags file (
DEVELOPMENT,
FORTRAN)
Návod, kniha: POSIX Programmer's Manual
ctags [-a][-f tagsfile]
pathname ...
ctags -x
pathname ...
The
ctags utility shall be provided on systems that support the User
Portability Utilities option, the Software Development Utilities option, and
either or both of the C-Language Development Utilities option and FORTRAN
Development Utilities option. On other systems, it is optional.
The
ctags utility shall write a
tagsfile or an index of objects
from C-language or FORTRAN source files specified by the
pathname
operands. The
tagsfile shall list the locators of language-specific
objects within the source files. A locator consists of a name, pathname, and
either a search pattern or a line number that can be used in searching for the
object definition. The objects that shall be recognized are specified in the
EXTENDED DESCRIPTION section.
The
ctags utility shall conform to the Base Definitions volume of
IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
- -a
- Append to tagsfile.
- -f tagsfile
- Write the object locator lists into tagsfile instead
of the default file named tags in the current directory.
- -x
- Produce a list of object names, the line number, and
filename in which each is defined, as well as the text of that line, and
write this to the standard output. A tagsfile shall not be created
when -x is specified.
The following
pathname operands are supported:
- file.c
- Files with basenames ending with the .c suffix shall
be treated as C-language source code. Such files that are not valid input
to c99 produce unspecified results.
- file.h
- Files with basenames ending with the .h suffix shall
be treated as C-language source code. Such files that are not valid input
to c99 produce unspecified results.
- file.f
- Files with basenames ending with the .f suffix shall
be treated as FORTRAN-language source code. Such files that are not valid
input to fort77 produce unspecified results.
The handling of other files is implementation-defined.
See the INPUT FILES section.
The input files shall be text files containing source code in the language
indicated by the operand filename suffixes.
The following environment variables shall affect the execution of
ctags:
- LANG
- Provide a default value for the internationalization
variables that are unset or null. (See the Base Definitions volume of
IEEE Std 1003.1-2001, Section 8.2, Internationalization
Variables for the precedence of internationalization variables used to
determine the values of locale categories.)
- LC_ALL
- If set to a non-empty string value, override the values of
all the other internationalization variables.
- LC_COLLATE
-
Determine the order in which output is sorted for the -x option. The
POSIX locale determines the order in which the tagsfile is
written.
- LC_CTYPE
- Determine the locale for the interpretation of sequences of
bytes of text data as characters (for example, single-byte as opposed to
multi-byte characters in arguments and input files). When processing
C-language source code, if the locale is not compatible with the C locale
described by the ISO C standard, the results are unspecified.
- LC_MESSAGES
- Determine the locale that should be used to affect the
format and contents of diagnostic messages written to standard error.
- NLSPATH
- Determine the location of message catalogs for the
processing of LC_MESSAGES .
Default.
The list of object name information produced by the
-x option shall be
written to standard output in the following format:
"%s %d %s %s", <object-name>, <line-number>, <filename>, <text>
where <
text> is the text of line <
line-number> of
file <
filename>.
The standard error shall be used only for diagnostic messages.
When the
-x option is not specified, the format of the output file shall
be:
"%s\t%s\t/%s/\n", <identifier>, <filename>, <pattern>
where <
pattern> is a search pattern that could be used by an
editor to find the defining instance of <
identifier> in
<
filename> (where
defining instance is indicated by the
declarations listed in the EXTENDED DESCRIPTION).
An optional circumflex (
'^' ) can be added as a prefix to
<
pattern>, and an optional dollar sign can be appended to <
pattern> to indicate that the pattern is anchored to the beginning
(end) of a line of text. Any slash or backslash characters in <
pattern> shall be preceded by a backslash character. The anchoring
circumflex, dollar sign, and escaping backslash characters shall not be
considered part of the search pattern. All other characters in the search
pattern shall be considered literal characters.
An alternative format is:
"%s\t%s\t?%s?\n", <identifier>, <filename>, <pattern>
which is identical to the first format except that slashes in <
pattern> shall not be preceded by escaping backslash characters, and
question mark characters in <
pattern> shall be preceded by
backslash characters.
A second alternative format is:
"%s\t%s\t%d\n", <identifier>, <filename>, <lineno>
where <
lineno> is a decimal line number that could be used by an
editor to find <
identifier> in <
filename>.
Neither alternative format shall be produced by
ctags when it is used as
described by IEEE Std 1003.1-2001, but the standard utilities
that process tags files shall be able to process those formats as well as the
first format.
In any of these formats, the file shall be sorted by identifier, based on the
collation sequence in the POSIX locale.
If the operand identifies C-language source, the
ctags utility shall
attempt to produce an output line for each of the following objects:
- *
- Function definitions
- *
- Type definitions
- *
- Macros with arguments
It may also produce output for any of the following objects:
- *
- Function prototypes
- *
- Structures
- *
- Unions
- *
- Global variable definitions
- *
- Enumeration types
- *
- Macros without arguments
- *
- #define statements
- *
- #line statements
Any
#if and
#ifdef statements shall produce no output. The tag
main is treated specially in C programs. The tag formed shall be
created by prefixing
M to the name of the file, with the trailing
.c, and leading pathname components (if any) removed.
On systems that do not support the C-Language Development Utilities option,
ctags produces unspecified results for C-language source code files. It
should write to standard error a message identifying this condition and cause
a non-zero exit status to be produced.
If the operand identifies FORTRAN source, the
ctags utility shall produce
an output line for each function definition. It may also produce output for
any of the following objects:
- *
- Subroutine definitions
- *
- COMMON statements
- *
- PARAMETER statements
- *
- DATA and BLOCK DATA statements
- *
- Statement numbers
On systems that do not support the FORTRAN Development Utilities option,
ctags produces unspecified results for FORTRAN source code files. It
should write to standard error a message identifying this condition and cause
a non-zero exit status to be produced.
It is implementation-defined what other objects (including duplicate
identifiers) produce output.
The following exit values shall be returned:
- 0
- Successful completion.
- >0
- An error occurred.
Default.
The following sections are informative.
The output with
-x is meant to be a simple index that can be written out
as an off-line readable function index. If the input files to
ctags
(such as
.c files) were not created using the same locale as that in
effect when
ctags -x is run, results might not be as expected.
The description of C-language processing says "attempts to" because
the C language can be greatly confused, especially through the use of
#defines, and this utility would be of no use if the real C
preprocessor were run to identify them. The output from
ctags may be
fooled and incorrect for various constructs.
None.
The option list was significantly reduced from that provided by historical
implementations. The
-F option was omitted as redundant, since it is
the default. The
-B option was omitted as being of very limited
usefulness. The
-t option was omitted since the recognition of
typedefs is now required for C source files. The
-u option was
omitted because the update function was judged to be not only inefficient, but
also rarely needed.
An early proposal included a
-w option to suppress warning diagnostics.
Since the types of such diagnostics could not be described, the option was
omitted as being not useful.
The text for
LC_CTYPE about compatibility with the C locale acknowledges
that the ISO C standard imposes requirements on the locale used to
process C source. This could easily be a superset of that known as "the C
locale" by way of implementation extensions, or one of a few alternative
locales for systems supporting different codesets. No statement is made for
FORTRAN because the ANSI X3.9-1978 standard (FORTRAN 77) does not (yet)
define a similar locale concept. However, a general rule in this volume of
IEEE Std 1003.1-2001 is that any time that locales do not match
(preparing a file for one locale and processing it in another), the results
are suspect.
The collation sequence of the tags file is not affected by
LC_COLLATE
because it is typically not used by human readers, but only by programs such
as
vi to locate the tag within the source files. Using the POSIX locale
eliminates some of the problems of coordinating locales between the
ctags file creator and the
vi file reader.
Historically, the tags file has been used only by
ex and
vi.
However, the format of the tags file has been published to encourage other
programs to use the tags in new ways. The format allows either patterns or
line numbers to find the identifiers because the historical
vi
recognizes either. The
ctags utility does not produce the format using
line numbers because it is not useful following any source file changes that
add or delete lines. The documented search patterns match historical practice.
It should be noted that literal leading circumflex or trailing dollar-sign
characters in the search pattern will only behave correctly if anchored to the
beginning of the line or end of the line by an additional circumflex or
dollar-sign character.
Historical implementations also understand the objects used by the languages
Pascal and sometimes LISP, and they understand the C source output by
lex and
yacc. The
ctags utility is not required to
accommodate these languages, although implementors are encouraged to do so.
The following historical option was not specified, as
vgrind is not
included in this volume of IEEE Std 1003.1-2001:
- -v
- If the -v flag is given, an index of the form
expected by vgrind is produced on the standard output. This listing
contains the function name, filename, and page number (assuming 64-line
pages). Since the output is sorted into lexicographic order, it may be
desired to run the output through sort -f. Sample use:
ctags -v files | sort -f > index vgrind -x index
The special treatment of the tag
main makes the use of
ctags
practical in directories with more than one program.
None.
c99 ,
fort77 ,
vi
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.