Makes a file
of tags to help locate objects in source files.
The ctags command creates a tags file for use with the ex and vi
editors from the specified C, Pascal, FORTRAN, yacc, lex, and LISP
source files. The tags file consists of locators of programming language
specific objects (such as functions and type definitions) within
the source files. A locator consists of the object name, the file
in which it is defined, and either a basic regular expression or
a line number that can be used in searching for the object definition.
Specifiers are given in separate fields on the line, separated by
spaces or tabs. Using the tags file, ex and vi can quickly find these
object definitions.
The following file
name suffixes are supported by the ctags command:
Item |
Description |
.c |
Treated as C-language source code and searched for C routine
and macro definitions. |
.h |
Treated as C-language source code and searched for C routine
and macro definitions. |
.f |
Treated as FORTRAN-language source code. |
.l |
Treated as LISP-language source code if its first nonspace
character is [ (open bracket), ( (open parenthesis),
or ; (semicolon). Treated as lex-language source code otherwise. |
File names ending with any other suffixes
are first examined to see if they contain any Pascal or FORTRAN routine
definitions. If not, they are processed again as C-language source
code. Files without a . (dot) suffix are processed as C-language
source code.
The main tag is treated
specially in C programs. The tag formed is created by prefixing M to the file name, removing a trailing .c (if any),
and removing the leading path name components. This makes use of ctags practical in directories with more than one program.
Notes:
- Recognition of the keywords function, an address specification for the subroutine, and procedure in FORTRAN and Pascal code ignores block
structure. The ctags command may yield inadequate results if
any two Pascal procedures have the same name, even though they are
in different blocks.
- The ctags command
does not recognize #if and #ifdef statements.
- If both the -B and -F options are specified, the last one specified will
take precedence.
- The -x option
takes precedence over any options (-a, -u, or -f) that would otherwise create a tags file.
- When the -v option is specified, the -x option is implied.
- The output of the ctags command is always sorted by object identifier.
Item |
Description |
-a |
Appends to the tags file. After appending, ctags sorts
the tags file. |
-B |
Causes ctags to use backward searching patterns (?.
. .?). |
-F |
Causes ctags to use forward searching patterns (/.
. ./). This is the default searching pattern. |
-f TagsFile |
Creates a tags file with the name specified by TagsFile instead of the default tags file. |
-m |
Causes ctags to not create tags for macro definitions. |
-o |
Causes ctags to generate line numbers for typedefs
instead of a basic regular expression which is used in searching
for the object definition. |
-t |
Creates tags for typedefs. This flag is on by default due
to standards conformance. |
-u |
Updates the specified files in tags; that is, all references
to them are deleted, and the new values are appended to the file.
This flag may slow the processing of the command. (It is usually
faster to simply rebuild the tags file.) |
-v |
Produces an index of the form expected by the vgrind command on the standard output. This listing contains the function
name, file name, and page number (assuming 64-line pages). |
-w |
Causes ctags to suppress diagnostic warning messages. |
-x |
Causes the ctags command to display a list of object
names, the line number and file name on which each is defined, as
well as the text of that line. This provides a simple, readable,
function index. If you specify this flag, the ctags command
does not build, update, or append a tags file, but writes to standard
output. |
- To write the output
of the ctags command to standard output for the C-language
source files, x.c, y.c, and z.c, enter:
- To create a tags
file named foo_tags for all the C-language source files within
the current directory, enter:
- To add additional
tags,including type definitions, to the foo_tags tags file
for the C-language source file zip.c, enter:
ctags -utf foo_tags zip.c
The following
exit values are returned:
Item |
Description |
0 |
Successful completion. |
>0 |
An error occurred. |
Item |
Description |
usr/bin/more/tags |
Output tags file. |