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Oracle® Developer Studio 12.6: C User's Guide

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Updated: July 2017
 
 

5.3 lint Command-Line Options

The lint program is a static analyzer. It cannot evaluate the runtime consequences of the dependencies it detects. For example, certain programs might contain hundreds of unreachable break statements that are of little importance that lint flags nevertheless. For example, you could use the lint command-line options and special directives embedded as comments in the source text, as follows:

  • Invoking lint with the -b option suppresses all the error messages about unreachable break statements.

  • Precede any unreachable statement with the comment /*NOT REACHED*/ to suppress the diagnostic for that statement.

The lint options are listed below alphabetically. Several lint options relate to suppressing lint diagnostic messages. These options are also listed in Table 14, following the alphabetized options, along with the specific messages they suppress.

lint recognizes many cc command-line options, including -A, -D, -E, -features=[no%]gcc_enums -fshort-enums, -fnoshort-enums -g, -g3, -gnone, -H, -O, -P, -pedantic, -U, -ansi, -std=value, -pedantic, -Xcsi, -Xa, -Xc, -Xs, -Xt, and -Y, -xhelp, -xhwcprof, -xkeep_unref, -#, -###, although -g, -g3, -gnone, -O, -xhelp, -xhwcprof, -xkeep_unref are ignored. Unrecognized options are warned about and ignored.

5.3.1 -#

Enables verbose mode, showing each component as it is invoked.

5.3.2 -###

Shows each component as it is invoked, but does not actually execute it.

5.3.3 -a

Suppresses certain messages. Refer to Table 14.

5.3.4 -b

Suppresses certain messages. Refer to Table 14.

5.3.5 -C filename

Creates a .ln file with the file name specified. These .ln files are the product of lint’s first pass only. filename can be a complete path name.

5.3.6 -c

Creates a .ln file consisting of information relevant to lint’s second pass for every .c file named on the command line. The second pass is not executed.

5.3.7 -dirout=dir

Specifies the directory dir where the lint output files (.ln files) will be placed. This option affects the -c option.

5.3.8 -err=warn

-err=warn is a macro for -errwarn=%all. See -errwarn=t.

5.3.9 -errchk=l(, l)

Perform additional checking as specified by l. The default is -errchk=%none. Specifying -errchk is equivalent to specifying -errchk=%all. l is a comma-separated list of checks that consists of one or more of the flags in the following table, for example, -errchk=longptr64,structarg.

Table 8  -errchk Flags
Value
Meaning
%all
Perform all of -errchk’s checks.
%none
Perform none of -errchk’s checks. This is the default.
[no%]locfmtchk
Check for printf-like format strings during the first pass of lint. Regardless of whether you use -errchk=locfmtchk, lint always checks for printf-like format strings in its second pass.
[no%]longptr64
Check portability to environment for which the size of long integers and pointers is 64 bits and the size of plain integers is 32 bits. Check assignments of pointer expressions and long integer expressions to plain integers, even when explicit cast is used.
Note that system header files define types intended to manipulate pointers. With the -m32 flag those types may be defined as base types like int that cannot safely manipulate a pointer, thus leading to false warnings. For example, usages of size_t:
#include <stdlib.h>
size_t
myfiunk(uint32_t param)
{
        return sizeof(uint64_t) * param;
}
.
$ lint -m32 -mux -errchk=longptr64 bug.c
(5) warning: assignment of 64-bit integer to 32-bit integer
$
[no%]structarg
Check structural arguments passed by value and report the cases when formal parameter type is not known.
[no%]parentheses
Check the clarity of precedence within your code. Use this option to enhance the maintainability of code. If -errchk=parentheses returns a warning, consider using additional parentheses to clearly signify the precedence of operations within the code.
[no%]signext
Check for situations in which the normal ISO C value-preserving rules allow the extension of the sign of a signed-integral value in an expression of unsigned-integral type. This option only produces error messages when you specify -errchk=longptr64 as well.
[no%]sizematch
Check for the assignment of a larger integer to a smaller integer and issue a warning. These warnings are also issued for assignment between same size integers that have different signs (unsigned int gets a signed int).

5.3.10 -errfmt=f

Specifies the format of lint output. f can be one of the following: macro, simple, src, or tab.

Table 9  -errfmt Flags
Value
Meaning
macro
Displays the source code, the line number, and the place of the error, with macro unfolding
simple
Displays the line number and the place number, in brackets, of the error, for one-line (simple) diagnostic messages. Similar to the -s option, but includes error-position information
src
Displays the source code, the line number, and the place of the error (no macro unfolding)
tab
Displays in tabular format. This is the default.

The default is -errfmt=tab. Specifying -errfmt is equivalent to specifying -errfmt=tab.

If more than one format is specified, the last format specified is used, and lint warns about the unused formats.

5.3.11 -errhdr=h

Limits the warnings from header files to the group of header files indicated by the flags in the following table:

Table 10  -errhdr Flags
Value
Meaning
%all
Checks all used header files
%none
Does not check header files
%user
Checks all used user header files, that is, all header files except those in /usr/include and its subdirectories, as well as those supplied by the compiler. This is the default.

Examples:

% lint -errhdr=inc1 -errhdr=../inc2

Checks used header files in directories inc1 and ../inc2.

% lint -errhdr=%all,no%../inc

Checks all used header files except those in the directory ../inc.

5.3.12 -erroff=tag(, tag)

Suppresses or enables lint error messages.

t is a comma-separated list that consists of one or more of the following: tag, no%tag, %all, %none.

Table 11  -erroff Flags
Value
Meaning
tag
Suppresses the message specified by this tag. You can display the tag for a message by using the -errtags=yes option.
no%tag
Enables the message specified by this tag
%all
Suppresses all messages
%none
Enables all messages. This is the default.

The default is -erroff=%none. Specifying -erroff is equivalent to specifying -erroff=%all.

Examples:

% lint -erroff=%all,no%E_ENUM_NEVER_DEF,no%E_STATIC_UNUSED

Prints only the messages “enum never defined” and “static unused” and suppresses other messages.

% lint -erroff=E_ENUM_NEVER_DEF,E_STATIC_UNUSED

Suppresses only the messages “enum never defined” and “static unused”.

5.3.13 -errsecurity=level

Use the -errsecurity option to check your code for security loopholes.

level must be one of the values shown in the following table.

Table 12  The -errsecurity Flags
level Value
Meaning
core
This level checks for source code constructs that are almost always either unsafe or difficult to verify. Checks at this level include:
  • Use of variable format strings with the printf() and scanf() family of functions

  • Use of unbounded string (%s) formats in scanf() functions

  • Use of functions with no safe usage: gets(), cftime(), ascftime(), creat()

  • Incorrect use of open() with O_CREAT

    Consider source code that produces warnings at this level to be a bug. The source code in question should be changed. In all cases, straightforward safer alternatives are available.

standard
This level includes all checks from the core level plus constructs that might be safe but have better alternatives available. This level is recommended when checking newly written code. Additional checks at this level include:
  • Use of string copy functions other than strlcpy()

  • Use of weak random number functions

  • Use of unsafe functions to generate temporary files

  • Use of fopen() to create files

  • Use of functions that invoke the shell

    Replace source code that produces warnings at this level with new or significantly modified code. Balance addressing these warnings in legacy code against the risks of destabilizing the application.

extended
This level contains the most complete set of checks, including everything from the core and standard levels. In addition, a number of warnings are generated about constructs that may be unsafe in some situations. The checks at this level are useful as an aid in reviewing code, but need not be used as a standard with which acceptable source code must comply. Additional checks at this level include:
  • Calls to getc() or fgetc() inside a loop

  • Use of functions prone to pathname race conditions

  • Use of the exec() family of functions

  • Race conditions between stat() and other functions

    Review source code that produces warnings at this level to determine whether the potential security issue is present.

%none
Disables -errsecurity checks

If you do not specify a setting for -errsecurity, the lint sets it to -errsecurity=%none. If you do specify -errsecurity but not an argument, the lint sets it to -errsecurity=standard.

5.3.14 -errtags=a

Displays the message tag for each error message. a can be either yes or no. The default is -errtags=no. Specifying -errtags is equivalent to specifying -errtags=yes.

Works with all -errfmt options.

5.3.15 -errwarn=t

If the indicated warning message is issued, lint exits with a failure status. t is a comma-separated list that consists of one or more of the following: tag, no%tag, %all, %none. The order of the tags is important. For example %all,no%tag causes lint to exit with a fatal status if any warning except tag is issued. The following table list the -errwarn values.

Table 13  -errwarn Flags
tag Value
Meaning
tag
Cause lint to exit with a fatal status if the message specified by this tag is issued as a warning message. Has no effect if tag is not issued.
no%tag
Prevent lint from exiting with a fatal status if the message specified by tag is issued only as a warning message. Has no effect if tag is not issued. Use this option to revert a warning message that was previously specified by this option with tag or %all from causing lint to exit with a fatal status when issued as a warning message.
%all
Cause lint to exit with a fatal status if any warning messages are issued. %all can be followed by no%tag to exempt specific warning messages from this behavior.
%none
Prevents any warning message from causing lint to exit with a fatal status should any warning message be issued.

The default is -errwarn=%none. Specifying -errwarn alone is equivalent to -errwarn=%all.

5.3.16 -F

Prints the path names as supplied on the command line rather than only their base names when referring to the .c files named on the command line.

5.3.17 -fd

Reports about old-style function definitions or declarations.

5.3.18 -flagsrc=file

Executes lint with options contained in the file file. Multiple options can be specified in file, one per line.

5.3.19 -h

Suppresses certain messages. Refer to Table 14.

5.3.20 -Idir

Searches the directory dir for included header files.

5.3.21 -k

Alter the behavior of /* LINTED [message] */ directives or NOTE(LINTED(message)) annotations. Normally, lint suppresses warning messages for the code following these directives. Instead of suppressing the messages, lint prints an additional message containing the comment inside the directive or annotation.

5.3.22 -Ldir

Searches for a lint library in the directory dir when used with -l.

5.3.23 -lx

Accesses the lint library llib-lx.ln.

5.3.24 -m

Suppresses certain messages. Refer to Table 14.

5.3.25 -m32|-m64

Specifies the data type model for the program being analyzed. Also searches for lint libraries that correspond to the selected data type model (32-bit or 64-bit).

–m64 is the default, except on Oracle Solaris 10 and 11 where –m32 is the default.

5.3.26 -n

Suppresses checks for compatibility with the default lint standard C library.

5.3.27 -ox

Causes lint to create a lint library with the name llib-lx.ln. This library is created from all the .ln files that lint used in its second pass. The -c option nullifies any use of the -o option. To produce a llib-lx.ln without extraneous messages, you can use the-x option. The -v option is useful if the source files for the lint library are only external interfaces. The lint library produced can be used later if lint is invoked with -lx.

5.3.28 -p

Enables certain messages relating to portability issues.

5.3.29 -Rfile

Write a .ln file to file, for use by cxref(1).

5.3.30 -s

Produce simple diagnostics with "warning:" or "error:" prefixes. By default, lint buffers some messages to produce compound output.

5.3.31 -u

Suppresses certain messages. Refer to Table 14. This option is suitable for running lint on a subset of files of a larger program.

5.3.32 -V

Writes the product name and releases to standard error.

5.3.33 -v

Suppresses certain messages. Refer to Table 14.

5.3.34 -Wfile

Write a .ln file to file, for use by cflow(1).

5.3.35 -XCC=a

Accepts C++-style comments. In particular, // can be used to indicate the start of a comment. a can be either yes or no. The default is -XCC=no. Specifying -XCC is equivalent to specifying -XCC=yes.


Note -  You only need to use this option when -std=c89 is in effect.

5.3.36 -Xalias_level[=l]

With this option, l is one of any, basic, weak, layout, strict, std, or strong. See Table 49 for a detailed explanation of the different levels of disambiguation.

If you do not specify -Xalias_level, the default of the flag is -Xalias_level=any, which means that no type-based alias-analysis is performed. If you specify -Xalias_level but do not supply a level, the default is -Xalias_level=layout.

Be sure to run lint at a level of disambiguation that is no more strict than the level at which you ran the compiler. If you run lint at a level of disambiguation that is more strict than the level at which you compiled, the results will be difficult to interpret and possibly misleading.

See lint Filters for a detailed explanation of disambiguation as well as a list of pragmas designed to help with disambiguation.

5.3.37 -Xarch=v9

(Oracle Solaris) Deprecated. Do not use. See -m32|-m64.

5.3.38 -Xc99[=o]

The -Xc99 flag controls compiler recognition of the implemented features from the C 99 standard (ISO/IEC 9899:1999, Programming Language -C).

o can be one of the following: all, none.

-Xc99=none disables recognition of C99 features. -Xc99=all enables recognition of supported C 99 features.

Specifying -Xc99 without any arguments is the same as -Xc99=all.

The -Xc99 flag cannot be used if the -std or -pedantic flag has been specified.

5.3.39 -Xkeeptmp=a

Keeps temporary files created during linting instead of deleting them automatically. a can be either yes or no. The default is -Xkeeptmp=no. Specifying -Xkeeptmp is equivalent to specifying -Xkeeptmp=yes.

5.3.40 -Xtemp=dir

Sets the directory for temporary files to dir. Without this option, temporary files go into /tmp.

5.3.41 -Xtime=a

Reports the execution time for each lint pass. a can be either yes or no. The default is -Xtime=no. Specifying -Xtime is equivalent to specifying -Xtime=yes.

5.3.42 -Xtransition=a

Issues warnings for the differences between K&R C and Oracle Developer Studio ISO C. a can be either yes or no. The default is -Xtransition=no. Specifying -Xtransition is equivalent to specifying -Xtransition=yes.

5.3.43 -Xustr={ascii_utf16_ushort|no}

This option enables recognition of string literals of the form U"ASCII-string" as an array of unsigned short int. The default is -Xustr=no, which disables compiler recognition of U"ASCII-string string literals. "-Xustr=ascii_utf16_ushort enables compiler recognition of U"ASCII-string" string literals.

5.3.44 -x

Suppresses certain messages. Refer to Table 14.

5.3.45 -y

Treats every .c file named on the command line as if it begins with the directive /* LINTLIBRARY */ or the annotation NOTE(LINTLIBRARY). A lint library is normally created using the /* LINTLIBRARY */ directive or the NOTE(LINTLIBRARY) annotation.