LINT(1) LINT(1)
NAME
lint - a C program checker
SYNOPSIS
lint [ option ] ... file ...
DESCRIPTION
The lint command attempts to detect features of the C
program files that are likely to be bugs, non-portable, or
wasteful. It also checks type usage more strictly than the
compilers. Among the things that are currently detected are
unreachable statements, loops not entered at the top,
automatic variables declared and not used, and logical
expressions whose value is constant. Moreover, the usage of
functions is checked to find functions that return values in
some places and not in others, functions called with varying
numbers or types of arguments, and functions whose values
are not used or whose values are used but none returned.
Arguments whose names end with .c are taken to be C source
files. Arguments whose names end with .ln are taken to be
the result of an earlier invocation of lint with either the
-c or the -o option used. The .ln files are analogous to .o
(object) files that are produced by the cc(1) command when
given a .c file as input. Files with other suffixes are
warned about and ignored.
lint will take all the .c, .ln, and llib-lx.ln (specified by
-lx) files and process them in their command line order. By
default, lint appends the standard C lint library (llib-
lc.ln) to the end of the list of files. However, if the -p
option is used, the portable C lint library (llib-port.ln)
is appended instead. When the -c option is not used, the
second pass of lint checks this list of files for mutual
compatibility. When the -c option is used, the .ln and the
llib-lx.ln files are ignored.
Any number of lint options may be used, in any order,
intermixed with file-name arguments. The following options
are used to suppress certain kinds of complaints:
-h Do not apply heuristic tests that attempt to intuit
bugs, improve style, and reduce waste.
-u Suppress complaints about functions and external
variables used and not defined, or defined and not
used. (This option is suitable for running lint on a
subset of files of a larger program).
-x Do not report variables referred to by external
declarations but never used.
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The following arguments alter lint's behavior:
-lx Include additional lint library llib-lx.ln. For
example, you can include a lint version of the math
library llib-lm.ln by inserting -lm on the command
line. This argument does not suppress the default use
of llib-lc.ln. These lint libraries must be in the
assumed directory. This option can be used to
reference local lint libraries and is useful in the
development of multi-file projects.
-n Do not check compatibility against either the standard
or the portable lint library.
-p Attempt to check portability to other dialects (IBM and
GCOS) of C. Along with stricter checking, this option
causes all non-external names to be truncated to eight
characters and all external names to be truncated to
six characters and one case.
-c Cause lint to produce a .ln file for every .c file on
the command line. These .ln files are the product of
lint's first pass only, and are not checked for inter-
function compatibility.
-o lib
Cause lint to create a lint library with the name
llib-llib.ln. The -c option nullifies any use of the
-o option. The lint library produced is the input that
is given to lint's second pass. The -o option simply
causes this file to be saved in the named lint library.
To produce a llib-llib.ln without extraneous messages,
use of the -x option is suggested. These option
settings are also available through the use of ``lint
comments'' (see below).
The -D, -U, and -I options of cpp(1) and the -g and -O
options of cc(1) are also recognized as separate arguments.
The -g and -O options are ignored, but, by recognizing these
options, lint's behavior is closer to that of the cc(1)
command. Other options are warned about and ignored. The
pre-processor symbol ``lint'' is defined to allow certain
questionable code to be altered or removed for lint.
Therefore, the symbol ``lint'' should be thought of as a
reserved word for all code that is planned to be checked by
lint.
Certain conventional comments in the C source will change
the behavior of lint:
/*NOTREACHED*/
at appropriate points stops comments about
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LINT(1) LINT(1)
unreachable code. [This comment is typically
placed just after calls to functions like
exit(2)].
/*VARARGSn*/
suppresses the usual checking for variable numbers
of arguments in the following function
declaration. The data types of the first n
arguments are checked; a missing n is taken to be
0.
/*LINTLIBRARY*/
at the beginning of a file shuts off complaints
about unused external declarations in this file.
This is equivalent to using the -v option.
lint produces its first output on a per-source-file basis.
Complaints regarding included files are collected and
printed after all source files have been processed.
Finally, if the -c option is not used, information gathered
from all input files is collected and checked for
consistency. At this point, if it is not clear whether a
complaint stems from a given source file or from one of its
included files, the source file name will be printed
followed by a question mark.
The behavior of the -c and the -o options allows for
incremental use of lint on a set of C source files.
Generally, one invokes lint once for each source file with
the -c option. Each of these invocations produces a .ln
file which corresponds to the .c file, and prints all
messages that are about just that source file. After all
the source files have been separately run through lint, it
is invoked once more (without the -c option), listing all
the .ln files with the needed -lx options. This will print
all the inter-file inconsistencies. This scheme works well
with make(1); it allows make to be used to lint only the
source files that have been modified since the last time the
set of source files were linted.
FILES
/usr/lib/lint the directory where the lint
libraries specified by the -lx
option must exist
/usr/lib/lint/llib-lcurses.ln
declarations for C Library
functions found in
/usr/lib/libcurses.a (binary
format; source is in
/usr/lib/lint/llib-lcurses.
/usr/lib/lint/llib-lgl.ln declarations for C Library
functions found in
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/usr/lib/libgl.a (binary format;
source is in
/usr/lib/lint/llib-lgl.
/usr/lib/lint/lint[12] first and second passes
/usr/lib/lint/llib-lc.ln declarations for C Library
functions (binary format; source
is in /usr/lib/lint/llib-lc )
/usr/lib/lint/llib-port.ln declarations for portable
functions (binary format; source
is in /usr/lib/lint/llib-port )
/usr/lib/lint/llib-lm.ln declarations for Math Library
functions (binary format; source
is in /usr/lib/lint/llib-lm )
/usr/tmp/*lint* temporaries
SEE ALSO
cc(1), cpp(1), make(1).
BUGS
exit(2), setjmp(3C), and other functions that do not return
are not understood; this causes various lies.
ORIGIN
AT&T V.3
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