Introduction

This Laboratory will cover the Unix C Code preprocessing tools  indent, cxref and lint.

indent      A  C program formatter which reads C programs from standard input or from specified files and writes them to standard output in a form that shows the structure of the code through indentations and spacing.

cxref      This tool analyzes a collection of C files and attempts to build a cross-reference table. The cxref manual page is available at   http://www.gedanken.demon.co.uk/

lclint       A   C program verifier. It attempts to detect features of the specified C programs on  command line that are likely to be bugs, to be non-portable, or to be wasteful.

Note: for more information, please see man pages for these commands and COG home page at http://intranet/COG/CogDocs/Linux_prog.html
 

The documentation for lclint is available only as a Postscript file . You will  need to install Postscript browser Ghostview to read the document. Add

source /local/config/cshrc.ghostview

to the LINUX section of your .cshrc file and then type

ghostview file.ps

in the command line to read the Postscript file file.ps
 

Examples

We'll use maxline.c from the Lab3 as a sample for running the preprocessing tools.

 In case you already don't have this command, add to your .cshrc  file

         source /local/config/cshrc.c-tools
 

indent

Key in the following in the command line

        indent  -bad -bc -i4 -l60  maxline.c -o  output_file
 

The above command formats the maxline.c and puts the output in a file called the output_file.

options:

        -bc    this puts  a NEWLINE after each comma in a declaration.

        -bad    this puts  a blank line after block of declaration.

        -i4     this sets the number of spaces for one indentation level to 4.

        -l60    this sets  maximum length of an output line with a trailing comment.

You can also refer to the man page of the indent by using the command

oso[2]% man indent

cxref
 

Key in the following in the command line

    cxref maxline.c -html -xref-all -CPP 'cpp -E -C -dD'

produces in the current directory an HTML file maxline.c.html containing cross reference table for all functions used in maxline.c program. You can browse this file by Netscape using File menu and then Open File option. You can use cxref without modifying the program.

Note: If you include in you mccabe program the header file <ctype.h> or any other header file which  in turn includes <endian.h> or <bytesex.h>, cxref will fail and  will give an esoteric message like

  "architecture not supported"

  This is because, in <bytesex.h> some macros are defined which  require the architecture of the machine to be specified.

 You can also refer to the online manual for cxref.

  One way out of the problem is to specifically define the macro  at the command line. For e.g. if maxline.c is your program then  you can give the following command

cxref maxline.c -html -D__i386__ -xref-all -CPP 'cpp -E -C -dD'

The output file that is created is  maxline.c.html .
 
 

lclint

Type in the command on the command line

lclint maxline.c

The typical output is something like this :

singapore:[9] lclint maxline.c
LCLint 2.4b --- 18 Apr 98

maxline.c: (in function main)
maxline.c:30:26: Value *save used before definition
  An rvalue is used that may not be initialized to a value on some execution
  path. (-usedef will suppress message)
maxline.c:31:2: Return value (type int) ignored: fflush(NULL)
  Result returned by function call is not used. If this is intended, can cast
  result to (void) to eliminate message. (-retvalint will suppress message)
maxline.c:32:2: Path with no return in function declared to return int
  There is a path through a function declared to return a value on which there
  is no return statement. This means the execution may fall through without
  returning a meaningful result to the caller. (-noret will suppress message)
maxline.c: (in function getline)
maxline.c:41:59: Operands of != have incompatible types (int, char): c != '\n'
  A character constant is used as an int. Use +charintliteral to allow
  character constants to be used as ints.  (This is safe since the actual type
  of a char constant is int.)
maxline.c:42:2: Assignment of int to char: s[i] = c
  To make char and int types equivalent, use +charint.
maxline.c:41:59: Incompatible types for != (int, char) (in post loop test):
                    c != '\n'
maxline.c:43:9: Operands of == have incompatible types (int, char): c == '\n'
maxline.c:45:4: Assignment of int to char: s[i] = c
maxline.c:9:5: Function exported but not used outside maxline: getline
  A declaration is exported, but not used outside this module. Declaration can
  use static qualifier. (-exportlocal will suppress message)
   maxline.c:50:1: Definition of getline
maxline.c:10:6: Function exported but not used outside maxline: copy
   maxline.c:63:1: Definition of copy

Finished LCLint checking --- 10 code errors found
singapore:[10]

lclint  warning messages are not too significant in this case, but in general could provide very useful hints about potential errors in the program. It makes sense to devote some time to read carefully the list of warnings that lclint generates after checking your source code.
 

Assignment   (10 points)

Use the C code preprocessing tools to reformat and check your McCabe Complexity C program from lab3.
 

• Use indent to reformat your C code such that the  new format

                        if (...)
                        {
                                code
                        }
 

• Build a function cross reference table for your C program using  cxref.

• Use lclint to test your C code.