240 lines
6.3 KiB
Groff
240 lines
6.3 KiB
Groff
.\" (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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.\" See the copyright notice in the ACK home directory, in the file "Copyright".
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.\"
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.\" $Id$
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.TH LINT 1 "$Revision$"
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.SH NAME
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lint \- a C program checker
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.SH SYNOPSIS
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.B lint
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[ \-abhuvx \-KR -ansi ] [file | libname | \-l\fIxxx\fP ] ...
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.br
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.B lint
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\-L\fIlibname\fP [ file | libname2 | \-l\fIxxx\fP ] ...
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.br
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.SH DESCRIPTION
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.I Lint
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does an extensive consistency and plausibility check on a set of C
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program files.
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When it detects a doubtful construction
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(which need not be an error) it gives a warning.
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.PP
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It does a full flow-of-control check, except that
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.BR goto s
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are not followed and that the fact that a function never returns
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is not propagated.
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If, however, no
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.BR goto s
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are used, each call of a non-returning function is followed by
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/*NOTREACHED*/ and each switch has a default clause (possibly consisting
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of /*NOTREACHED*/), the initialization state of all local variables will
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be checked correctly.
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.PP
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.I Lint
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checks the types of the arguments implied by the format in a call of
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.IR printf() ,
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.IR scanf()
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and family, if the format string is a direct argument in the call.
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Formats of user functions can be indicated using a FORMAT pseudo-comment; see
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below.
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.PP
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.I Libraries
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.PP
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The second command (using the
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.BR \-L -option)
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is used to maintain lint libraries; these are ASCII files
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that contain the output of the first pass.
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A library name ends in
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.BR .llb .
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A lint user library can be created and updated by using the
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.B \-L
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option. The
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.I libname
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end in
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.BR .llb ,
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and can be passed to
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.I lint
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again as a normal argument.
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.PP
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Standard libraries are searched by default or by explicitly giving the
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.B \-l
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option; their format is identical to that of the user library files.
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Possibilities are
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.BR \-lm ,
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.B \-ltermcap
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and
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.BR \-lcurses .
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.B \-lc
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is default; a single
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.B \-l
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tells
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.I lint
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not to use the standard C library.
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The standard libraries are searched for in the standard lint directory or
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in the directory given in the environment variable LINTLIB, if present.
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.PP
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.I Options
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.PP
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The
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.BR \-D ,
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.B \-U
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and
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.B \-I
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options are recognized as separate arguments and conform to those of
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.IR cc .
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The
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.B \-KR
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option tells
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.I lint
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to check strictly according to Kernighan & Ritchie; since
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.I lint
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is trying to be helpful rather than obnoxious, this is not the default.
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The
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.B \-ansi
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option tells lint to check according to ANSI C.
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.PP
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.I Lint
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understands the following additional options:
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.TP
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.B a
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Warn about conversions that may cause a loss of precision.
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.TP
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.B b
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Do not report not-reachable
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.I break
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statements.
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This flag may be useful when
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.I lint
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is run on a generated source file.
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.TP
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.B h
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Apply several heuristics:
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signal "null effects", possible pointer alignment problems and odd
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constructs; report definitions of variables that have a scope wider than
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necessary: extern variables that are used in one file only, automatic
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variables that could be more local.
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.TP
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.B u
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Do not complain about unused and undefined functions and global variables.
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.TP
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.B v
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Do not warn about unused arguments of functions.
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.TP
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.B x
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Complain about unused external variables.
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.PP
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.I Pseudo-comments
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.PP
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The following pseudo-comments can be used to influence the behaviour of
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.IR lint:
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.TP
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/*\ ARGSUSED\ */
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Do not warn about arguments not used in the next function
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(see also the \-\fBv\fR option).
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.TP
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/*\ NOTREACHED\ */
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This tells
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.I lint
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that the flow of control "cannot reach" this comment.
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This is a way to tell
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.I lint
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that a statement never "returns".
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.TP
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/*\ LINTLIBRARY\ */
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The definitions following this pseudo-comment are assumed to be part of a
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library.
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It suppresses complaints about unused functions and variables
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and is used in the creation of lint libraries.
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It implies /*\ ARGSUSED\ */.
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.TP
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/*\ VARARGS\fIn\fR\ */
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The next function can be called with a variable number of
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arguments.
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Only check the types of the first \fIn\fR arguments.
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The \fIn\fR must follow the word VARARGS immediately.
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/*\ VARARGS0\ */ may be abbreviated to /*\ VARARGS\ */.
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.TP
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/*\ FORMAT\fIn\fR $ ... $\ */
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The \fIn\fP-th argument (counting from 0) of the next function declaration
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corresponds to a
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.IR printf -like
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format string. Details about the format are given between the $$; see below.
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A missing $$ repeats the latest format.
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The \fIn\fR must follow the word FORMAT immediately.
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/*\ FORMAT\fIn\fR $ ... $\ */ implies /*\ VARARGS\fIn+1\fP\ */; if the format
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is followed by more required arguments, a separate /*\ VARARGS\fIm\fP\ */
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must be given after the FORMAT pseudo-comment.
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.IP
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If the printf-like heading also has to conform to some varargs.h convention,
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error messages may result; these can be suppressed by appending the letter v
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to the word FORMAT\fIn\fR without intervening space.
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.PP
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.I Formats
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.PP
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The $$-part of the FORMAT pseudo-comment consists of a list of format
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specifications, each of the form
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.IR %T = type ,
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where
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.I T
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is an arbitrary (short) string and
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.I type
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is the expected type in "C normal form" (like in a cast, with no superfluous
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parentheses and without the use of typedefs). E.g., %ld=long indicates that
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the format string ld corresponds to a parameter of type long. For a shorter
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notation see the example below.
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.I Lint
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recognizes conversion specifications of the form %[N|*|][.[N|*]]T where N is
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a number, the * is itself and T is a string as defined above. For the above
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example this would include %ld, %5.2ld, %.*ld, etc.
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.PP
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Example: the FORMAT pseudo-comment for
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.I printf()
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is:
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.br
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/*\ FORMAT0 $
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.br
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%[dox] = int %l[dox] = long %[DOX] = long
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.br
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%u = unsigned int %lu = unsigned long %U = unsigned long
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.br
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%[feg] = double
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.br
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%c = int %s = char *
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.br
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$\ */
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.PP
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.I Output
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.PP
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Some users feel it is a good idea to pipe the output of
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.I lint
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through the command
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.br
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sort \-t' ' +0d \-1 +2n \-3
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.br
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where the character between the apostrophes is a space.
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.SH "ENVIRONMENT VARIABLES"
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LINTFLAGS additional flag arguments (e.g. LINTFLAGS=\-h)
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.br
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LINTLIB directory in which the standard libraries are looked up
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.SH FILES
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.IP ???/lnt 24
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first pass
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.IP ???/lpass2/lpass2
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second pass
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.IP ???/llib/*.llb
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lint libraries
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.SH SEE ALSO
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cem(1)
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.br
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Frans Kunst,
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.I Lint, a C Program Checker
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.SH BUGS
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Conflicting options in the command line are not detected.
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.br
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After a label, all automatic variables are assumed initialized.
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.SH AUTHOR
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Frans Kunst, Vrije Universiteit, Amsterdam.
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.br
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Dick Grune, Vrije Universiteit, Amsterdam.
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.br
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