MISRA Discussion Forums
What about Macros for 14.3? - Printable Version

+- MISRA Discussion Forums (https://forum.misra.org.uk)
+-- Forum: MISRA C (https://forum.misra.org.uk/forumdisplay.php?fid=4)
+--- Forum: MISRA-C: 2004 rules (https://forum.misra.org.uk/forumdisplay.php?fid=17)
+---- Forum: 6.14 Control Flow (https://forum.misra.org.uk/forumdisplay.php?fid=46)
+---- Thread: What about Macros for 14.3? (/showthread.php?tid=19)

What about Macros for 14.3? - gs - 20-12-2004

Expanding upon the example in the MISRA 2004 Standard for 14.3:


#define WHATABOUTTHIS /* Um */ ;
#define ORTHIS
#define ANDTHISTOO /* Well, I, uh... */

void f()
{
; /* OK */
/* Not OK */ ;
;/* Not OK */
WHATABOUTTHIS
ORTHIS;
ANDTHISTOO;
}

Which of the lines with macros, if any, violate the Rule?

- Gavin McCall - 09-09-2005

Code:
#define M1 ;

This macro breaks rule 19.4. Macro expanding to Null statement is not allowed.

Code:
#define M2
#define M3 /* comment */

This macro expands to no body, and is therefore not prohibited by 19.4.

A comment in a macro definition is removed by the pre-processor. Rule 14.3 applied before
Pre-processing. Treatment of M2 and M3 is identical.

Code:
M1

Since definition of M1 macro was invalid, its use is already a violation.

Code:
M2;
M3;

After pre-processing, these are both Null statements. Before pre-processing, there are characters before the Null statement. This is not allowed by 14.3.

- misra-c - 29-08-2006

Quote:
Code:
#define M1 ;


This macro breaks rule 19.4. Macro expanding to Null statement is not allowed.

Code:
#define M2
#define M3 /* comment */


This macro expands to no body, and is therefore not prohibited by 19.4.

A comment in a macro definition is removed by the pre-processor. Rule 14.3 applied before
Pre-processing. Treatment of M2 and M3 is identical.

Code:
M1


Since definition of M1 macro was invalid, its use is already a violation.

Code:
M2;
M3;

After pre-processing, these are both Null statements. Before pre-processing, there are characters before the Null statement. This is not allowed by 14.3.

Re-posted under offical user name only.