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+---- Forum: 8.13 Side effects (https://forum.misra.org.uk/forumdisplay.php?fid=168)
+---- Thread: 13.3 Should side effects be allowed in comma expressions? (/showthread.php?tid=1781)
13.3 Should side effects be allowed in comma expressions? - Loïc - 31-08-2026
In a comma expression (which is discouraged by another advisory rule, 12.3, but could still be used), there is a clear separation in term of execution between what comes before and what comes after the comma. Therefore, I think the rationale is not very strong in this case.
What would you think of relaxing 13.3 and making this example compliant (it would still be non-compliant with 12.3):
Code:
int f(int n, int*dest) {
for (int i = 0 ; i<10 ; ++i, ++dest) { // Currently non-compliant
*dest = i*i;
}
}RE: 13.3 Should side effects be allowed in comma expressions? - misra-c - 08-10-2026
The example also violates Rule 14.2 - the third term can only modify the loop counter
The MISRA C WG agrees that this is an unnecessary violation of Rule 13.3, and will consider refinement [ID: 481 applies].