lint Message Formats

The lint program can, with certain options, show precise source file lines with pointers to the line position where the error occurred. The option enabling this feature is -errfmt=f. Under this option, lint provides the following information:

• Source line(s) and position(s)

• Macro unfolding

• Error-prone stack(s)

For example, the following program, Test1.c, contains an error.

1 #include <string.h>
2 static void cpv(char *s, char* v, unsigned n)
3 { int i;
4   for (i=0; i<=n; i++)
5        *v++ = *s++;
6 }
7 void main(int argc, char* argv[])
8 {
9 	if (argc != 0)
10	   cpv(argv[0], argc, strlen(argv[0]));
11}

Using lint on Test1.c with the option:

% lint -errfmt=src Test1.c

produces the following output:

      |static void cpv(char *s, char* v, unsigned n)
      |            ^  line 2, Test1.c
      |
      |	   cpv(argv[0], argc, strlen(argv[0]));
      |	                ^  line 10, Test1.c
warning: improper pointer/integer combination: arg #2
      |
      |static void cpv(char *s, char* v, unsigned n)
      |                               ^  line 2, Test1.c
      |        *v++ = *s++;
      |         ^  line 5, Test1.c
warning: modification using a pointer produced in a questionable way
	v defined at Test1.c(2)	::Test1.c(5)
	  call stack:
		  main()                ,	Test1.c(10)
		  cpv()                 ,	Test1.c(5)

The first warning indicates two source lines that are contradictory. The second warning shows the call stack, with the control flow leading to the error.

Another program, Test2.c, contains a different error:

1 #define AA(b) AR[b+l]
2 #define B(c,d) c+AA(d)
3
4 int x=0;
5
6 int AR[10]={1,2,3,4,5,6,77,88,99,0};
7
8 main()
9  {
10  int y=-5, z=5;
11  return B(y,z);
12 }

Using lint on Test2.c with the option:

% lint -errfmt=macro Test2.c

produces the following output, showing the steps of macro substitution:

      | return B(y,z);
      |        ^  line 11, Test2.c
      |
      |#define B(c,d) c+AA(d)
      |                 ^  line 2, Test2.c
      |
      |#define AA(b) AR[b+l]
      |                   ^  line 1, Test2.c
error: undefined symbol: l