Page History

...

Non-compliant Code Example 3

The order of evaluation of arguments to a function is undefined.

func(i++, i++);

Compliant Solution

The following solution is appropiate when the programmer intends for both arguments to func() to be equivalent:

i++;
func(i, i);

The following solution is appropiate when the programmer intends for the second argument to be one greater than the first:

j = i;
j++;
func(i, j);

Consequences

References

• ISO/IEC 9899-1999 Section 5.1.2.3 Program execution
• ISO/IEC 9899-1999 Section 6.5 Expressions
• ISO/IEC 9899-1999 Annex C Sequence points
• comp.lang.c FAQ list - Questions 3.1, 3.2, 3.3, 3.3b, 3.7, 3.8, 3.9, 3.10a, 3.10b, 3.11