6.5.17 Comma operator
Syntax
expression:
assignment-expression
expression , assignment-expression
Semantics
The left operand of a comma operator is evaluated as a void expression; there is a sequence point after its evaluation. Then the right operand is evaluated; the result has its type and value.[1] If an attempt is made to modify the result of a comma operator or to access it after the next sequence point, the behavior is undefined.
EXAMPLE As indicated by the syntax, the comma operator (as described in this subclause) cannot appear in contexts where a comma is used to separate items in a list (such as arguments to functions or lists of initializers). On the other hand, it can be used within a parenthesized expression or within the second expression of a conditional operator in such contexts. In the function call
f(a, (t=3, t+2), c)
the function has three arguments, the second of which has the value 5.
Forward References
Footnotes