MirBSD manpage: lint(1)

LINT(1)                      BSD Reference Manual                      LINT(1)


     lint - a C program verifier


     lint [-ceFfgHhprsVvxz] [-i | -nu] [-Dname[=def]] [-Idirectory]
          [-Ldirectory] [-llibrary] [-MD] [-ooutputfile] [-Uname] file ...
     lint [-ceFfgHhprsVvz] -Clibrary [-Dname[=def]] [-Idirectory] [-MD]
          [-Uname] file ...


     lint attempts to detect features of the named C program files that are
     likely to be bugs, non-portable, or wasteful. It also performs stricter
     type checking than the C compiler. lint runs the C preprocessor as its
     first phase, with the preprocessor symbol lint defined to allow certain
     questionable code to be altered or skipped by lint. Therefore, this sym-
     bol should be thought of as a reserved word for all code that is to be
     checked by lint.

     Among the possible problems that are currently noted are unreachable
     statements, loops not entered at the top, variables declared and not
     used, and logical expressions with constant values. Function calls are
     checked for inconsistencies, such as calls to functions that return
     values in some places and not in others, functions called with varying
     numbers of arguments, function calls that pass arguments of a type other
     than the type the function expects to receive, functions whose values are
     not used, and calls to functions not returning values that use the non-
     existent return value of the function.

     Filename arguments ending with .c are taken to be C source files.
     Filename arguments with names ending with .ln are taken to be the result
     of an earlier invocation of lint, with either the -i, -o, or -C option in
     effect. The .ln files are analogous to the .o (object) files produced by
     cc(1) from .c files. lint also accepts special libraries specified with
     the -l option, which contain definitions of library routines and vari-

     lint takes all the .c, .ln, and llib-llibrary.ln (lint library) files and
     processes them in command-line order. By default, lint appends the stan-
     dard C lint library (llib-lc.ln), if it exists, to the end of the list of
     files. When the -i option is used, the .ln files are ignored. Also, when
     the -o or -i options are used, the llib-llibrary.ln files are ignored.
     When the -i option is omitted the second pass of lint checks this list of
     files for mutual compatibility. At this point, if a complaint stems not
     from a given source file, but from one of its included files, the source
     filename will be printed followed by a question mark.

     The options are as follows:

             Create a lint library with the name llib-llibrary.ln. This li-
             brary is built from all .c and .ln input files. After all global
             definitions of functions and variables in these files are written
             to the newly created library, lint checks all input files, in-
             cluding libraries specified with the -l option, for mutual compa-

     -c      Complain about casts which have questionable portability.

             Define name for cpp(1), as if by a #define directive. If no de-
             finition is given, name is defined as 1.

     -e      Complain about unusual operations on enum-Types and combinations
             of enum- and integer-Types.

     -F      Print pathnames of files. lint normally prints the filename
             without the path.

     -f      For each warning or error, print the offending line of the
             corresponding source code file.

     -g      Don't print warnings for some extensions of gcc(1) to the C
             language. Currently these are nonconstant initializers in au-
             tomatic aggregate initializations, arithmetic on pointer to void,
             zero sized structures, subscripting of non-lvalue arrays, proto-
             types overriding old style function declarations and long long
             integer types. The -g flag also turns on the keywords asm and
             inline (alternate keywords with leading underscores for both asm
             and inline are always available).

     -H      If a complaint stems from an included file lint prints the name
             of the included file instead of the source file name followed by
             a question mark.

     -h      Apply a number of heuristic tests to attempt to intuit bugs, im-
             prove style, and reduce waste.

             Add directory to the list of directories in which to search for
             include files.

     -i      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 compatibility between functions.

             Search for lint libraries in directory and directory/lint before
             searching the standard place.

             Include the lint library llib-llibrary.ln.

     -MD     Ignored, so the same flags can be passed to lint and cpp(1).

     -n      Do not check compatibility against the standard library.

             Name the output file outputfile. The output file produced is the
             input that is given to lint's second pass. The -o option simply
             saves this file in the named output file. If the -i option is
             also used the files are not checked for compatibility. To produce
             a llib-llibrary.ln without extraneous messages, use of the -u op-
             tion is suggested. The -v option is useful if the source file(s)
             for the lint library are just external interfaces.

     -p      Attempt to check portability of code to other dialects of C.

     -r      In case of redeclarations report the position of the previous de-

     -s      Strict ANSI C mode. Issue warnings and errors required by ANSI C.
             Also do not produce warnings for constructs which behave dif-
             ferently in traditional C and ANSI C. With the -s flag,
             __STRICT_ANSI__ is a predefined preprocessor macro.

     -Uname  Remove any initial definition of name for the preprocessor.

     -u      Do not complain about functions and external variables used and
             not defined, or defined and not used (this is suitable for run-
             ning lint on a subset of files comprising part of a larger pro-

     -V      Print the command lines constructed by the controller program to
             run the C preprocessor and lint's first and second pass.

     -v      Suppress complaints about unused arguments in functions.

     -x      Report variables referred to by extern declarations, but never

     -z      Do not complain about structures that are never defined (for ex-
             ample, using a structure pointer without knowing its contents).

     Input Grammar

     lint's first pass reads standard C source files. lint recognizes the fol-
     lowing C comments as commands.

     /* ARGSUSEDn */
                 Make lint check only the first n arguments for usage; a miss-
                 ing n is taken to be 0 (this option acts like the -v option
                 for the next function).

                 Suppress complaints about constant operands for the next ex-

     /* FALLTHRU */ or /* FALLTHROUGH */
                 Suppress complaints about fall through to a case or default
                 labelled statement. This directive should be placed immedi-
                 ately preceding the label.

     /* LINTLIBRARY */
                 At the beginning of a file, mark all functions and variables
                 defined in this file as used. Also shut off complaints about
                 unused function arguments.

     /* LINTED [comment] */ or /* NOSTRICT [comment] */
                 Suppress any intra-file warning except those dealing with
                 unused variables or functions. Warnings about unused static
                 variables can be suppressed by prefixing the variable name
                 with __LINTED__ instead. This directive should be placed on
                 the line immediately preceding where the lint warning oc-

     /* LONGLONG */
                 Suppress complaints about use of long long integer types.

     /* NORETURN */
                 Tell lint that the function will never return, which means
                 any code following a call to this function is unreachable.
                 This directive should be placed immediately preceding the

     /* NOTREACHED */
                 At appropriate points, inhibit complaints about unreachable
                 code. This comment is typically placed just after calls to
                 functions like exit(3).

     /* PRINTFLIKEn */
                 Make lint check the first (n-1) arguments as usual. The n-th
                 argument is interpreted as a printf format string that is
                 used to check the remaining arguments.

     /* PROTOLIBn */
                 Cause lint to treat function declaration prototypes as func-
                 tion definitions if n is non-zero. This directive can only be
                 used in conjunction with the /* LINTLIBRARY */ directive. If
                 n is zero, function prototypes will be treated normally.

     /* SCANFLIKEn */
                 Make lint check the first (n-1) arguments as usual. The n-th
                 argument is interpreted as a scanf format string that is used
                 to check the remaining arguments.

     /* VARARGSn */
                 Suppress 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.

     The behavior of the -i 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 -i option. Each of these invocations produces a
     .ln file that 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 -i op-
     tion), listing all the .ln files with the needed -llibrary options. This
     will print all the inter-file inconsistencies. This scheme works well
     with make(1); it allows make(1) to be used to lint only the source files
     that have been modified since the last time the set of source files were


     LIBDIR      the directory where the lint libraries specified by the
                 -llibrary option must exist. If this environment variable is
                 undefined, then the default path /usr/libdata/lint will be
                 used to search for the libraries.

     TMPDIR      usually the path for temporary files can be redefined by set-
                 ting this environment variable.


     /usr/libexec/lint[12]             programs
     /usr/libdata/lint/llib-lposix.ln  prebuilt POSIX C lint library
     /usr/libdata/lint/llib-lstdc.ln   prebuilt ANSI/ISO C lint library
     /tmp/lint*                        temporaries


     cc(1), cpp(1), make(1)


     Jochen Pohl


     The routines exit(3), longjmp(3) and other functions that do not return
     are not understood; this causes various incorrect diagnostics.

     Static functions which are used only before their first extern declara-
     tion are reported as unused.

     Libraries created by the -o option will, when used in later lint runs,
     cause certain errors that were reported when the libraries were created
     to be reported again, and cause line numbers and file names from the ori-
     ginal source used to create those libraries to be reported in error mes-
     sages. For these reasons, it is recommended to use the -C option to
     create lint libraries.

MirBSD #10-current              March 23, 2014                               3

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