+- 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: 6.19 Preprocessing Directives (https://forum.misra.org.uk/forumdisplay.php?fid=43)
+---- Thread: Rule 19.16 (/showthread.php?tid=205)
Rule 19.16 - nikunj - 02-02-2006
The syntax errors the rule talks about would any way be reflected as an sytax error by the compiler.
for example in
#defineNAME \"test\"
the complier would return an error.
So in effect the rule becomes redundant!
- lv - 02-02-2006
The compiler does not produce an error if the syntax error is inside a condition compilation branch which are not \"selected\".
Example:
Code:
#define AAA 2
int foo(void)
{
int x;
#ifndef AAA
x = 1;
rlhegsfldghsfdghlsfd
#else
x = 0;
#endif
return(x);
}This code will not produce an error, because AAA is define and so, the syntax error is inside the exclued code.
In the MISRA example:
Code:
#define AAA 2
int foo(void)
{
int x;
#ifndef AAA
x = 1;
#else1
x = 0;
#endif
return(x);
}If AAA is defined then all code after the #ifndef is ignored until a #else, #elif or #endif instruction. In the example, there is a syntax error on #else and so, if AAA is define all code between #ifndef and #endif will be exclued and the result code will be, without any error:
Code:
#define AAA 2
int foo(void)
{
int x;
return(x);
}But the desired behavior was certainly:
Code:
#define AAA 2
int foo(void)
{
int x;
x = 0;
return(x);
}So, this rule is not redundant.
- misra-c - 27-04-2006
We agree with LV's answer.