LINT(1)                 System General Commands Manual                 LINT(1)

NAME
     lint - a program for C language source code checking

SYNOPSIS
     lint [-abceFghHprvVxz] [-s|-t] [-i|-nu] [-Dname[=def]] [-Uname]
          [-Idirectory] [-Ldirectory] [-llibrary] [-ooutputfile] file ...
     lint [-abceFghHprvVz] [-s|-t] -Clibrary [-Dname[=def]] [-Idirectory]
          [-Uname] file ...

DESCRIPTION
     The program lint attempts to detect features of the named C program files
     that are likely to be errors, may cause errors, may cause errors to go
     undetected, to be non-portable, or to be wasteful.  It also performs
     stricter type checking than most C compilers.  During the first phase of
     lint the C preprocessor (with the macro symbol lint defined) is run to
     allow selected code that may be questionable to be altered or skipped.
     Therefore, the lint macro should be treated by the user as a reserved
     word for all C language code that will to be checked by lint.

     This C language checker can be run by user on the command line. But more
     typically for projects with more than a couple of source files the use of
     lint will be controlled by a build tool such as make or jam.

OPTIONS
     -a      Report assignments of long values to variables that are not long.

     -aa     Additional to -a, report all assignments of integer values to
             other integer values which cause implicit narrowing conversion.

     -b      Report break statements that cannot be reached.  The default is
             to not report break statements that cannot be reached because
             most lex(1) and many yacc(1) outputs produce many such com-
             plaints. Note: this setting is the opposite of many other ver-
             sions of lint.

     -c      Complain about casts which have questionable portability.

     -Clibrary
             Create a lint library with the name llib-llibrary.ln.  This
             library 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, including libraries specified with the -l option, for
             mutual compatibility.

     -Dname[=def]
             Define name for cpp(1) (the pre-processor), as if by a #define
             directive.  If no definition is given, name is defined as 1. See
             also -U.

     -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.

     -g      Don't print warnings for some extensions of gcc(1) to the C lan-
             guage.  Currently these are nonconstant initializers in automatic
             aggregate initializations, arithmetic on pointer to void, zero
             sized structures, subscripting of non-lvalue arrays, prototypes
             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      Apply a number of heuristic tests to attempt to intuit bugs,
             improve style, and reduce waste. Note: this flag setting is the
             opposite of some other lint's.

     -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.

     -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.

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

     -llibrary
             Include the lint library llib-llibrary.ln.

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

     -n      Do not check compatibility against the standard (default)
             library.

     -ooutputfile
             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 pro-
             duce a llib-llibrary.ln without extraneous messages, use of the
             -u option 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
             declaration.

     -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.

     -t      Traditional C mode.  __STDC__ is not predefined in this mode.
             Warnings are printed for constructs not allowed in traditional C.
             Warnings for constructs which behave differently in traditional C
             and ANSI C are suppressed.  Preprocessor macros describing the
             machine type (e.g., sun3) and machine architecture (e.g., m68k)
             are defined without leading and trailing underscores.  The key-
             words const, volatile and signed are not available in traditional
             C mode (although the alternate keywords with leading underscores
             still are).

     -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-
             gram).

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

     -v      Suppress complaints about unused arguments in functions.

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

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

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

BEHAVIOR
     Filename arguments ending with .c are understood to be C source files.
     Header files (ending in .h) are not to be specified because they will be
     discovered as the C code #include's these files.  Filenames with names
     ending with .ln are understood to be lint processed files from an earlier
     invocation of lint.  Files ending in .ln are the result of using one of
     the options -C, -i, or -o options.  The .ln files are analogous to .o
     (object) files produced by a compiler using .c files.  Special lint
     libraries are to be specified with the -l option. These special lint
     libraries contain definitions of certain system library and header proto-
     types, definitions and declarations not specified with the immediate C
     code files.

     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
     default lint library (llib-lc.ln) (when it can be found; x-ref LIBDIR) 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 com-
     plaint 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 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
     option), 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 linted.

SPECIAL DIRECTIVES
     lint's first pass reads standard C source files.  lint recognizes the
     following C comments as lint commands.

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

     /* CONSTCOND */ or /* CONSTANTCOND */ or /* CONSTANTCONDITION */
                 suppress complaints about constant operands for the next
                 expression.

     /* 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] */
                 Suppresses any intra-file warning except those dealing with
                 unused variables or functions.  This directive should be
                 placed on the line immediately preceding where the lint warn-
                 ing occurred.

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

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

     /* PRINTFLIKEn */
                 makes 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 */
                 causes 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 */
                 makes 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.

EXAMPLES
     The following are some small examples of using lint from the command line
     and with make(1).

     Single File
                 lint foo.c

     Single File with additional packages
                 lint -I/usr/local/include foo.c

     Multiple Files
                 lint -i bar.c foo.c
                 lint bar.ln foo.ln

     Multiple Files with additional packages
                 lint -I/usr/local/include -i bar.c foo.c
                 lint bar.ln foo.ln

     Single X11 File
                 lint fooX11.c -lX11

     Make Recipe
                 SRCS= bar.c foo.c
                 LNS= ${SRCS:.c=.ln}
                 $(LNS): $(SRCS)
                      lint -I ../../include -i ${@:.ln=.c}
                 lint: $(LNS)
                      lint $>

ENVIRONMENT
     LIBDIR      directory where the lint libraries specified by -llibrary
                 must exist.  The default path /usr/local/libdata/lint will be
                 used to search for the libraries when this environment vari-
                 able is not set.

     TMPDIR      temporary directory where intermediate files reside.

FILES
     /usr/local/libexec/lint1          first pass program
     /usr/local/libexec/lint2          second pass program
     /usr/local/libdata/lint/llib-lc.ln
                                       prebuilt (default) lint library
     /usr/local/libdata/lint/llib-lX11.ln
                                       prebuilt X11 lint library

LINT LIBRARIES
     Currently two lint libraries are included: "C" and "X11". The "C" library
     (llib-lc.ln) encapsulates all of the functions shipped with Interix
     except for the X11 libraries. This includes the traditional C library as
     well as the libraries for pthreads, crypt, curses, rpc, sockets, xti, lex
     and yacc.  The "X11" library (llib-lc.ln) encapsulates the majority of
     the X11 family such as X11, Xt, Xmu, Xpm, rgb, Xi, Xext, ICE, Xaw, Xau,
     FS, etc.  Additional libraries are available upon request (i.e. Motif if
     you have purchased the Motik SDK).

SEE ALSO
     cc(1), c89(1), cpp(1), gcc(1), jam(1), make(1)

CAVEATS
     Some function calls with a program are never intended to be returned
     from.  The API's exit(3) and longjmp(3) are good examples of such func-
     tions. In many standard utilities a call to usage() will not be returned
     from. In these situations the specialized C comment "/* NOTREACHED */"
     should follow the specific line in the C source code to supress lint from
     giving a warning about the code.

     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
     original source used to create those libraries to be reported in error
     messages.  For these reasons, it is recommended to use the -C option to
     create lint libraries.

     The functionality of the options to lint may vary from other instances of
     the utility. This due to their different heritages.

SUPPORT
     For support or to request additional enhancements please contact .

BSD                            September 8, 2004                           BSD