Rules:
8.1.a. The comma operator (,) shall not be used within variable declarations.
Example:
char * x, y; // Was y intended to be a pointer also? Don’t do this.
Reasoning: The cost of placing each declaration on a line of its own is low. By contrast, the risk that either the compiler or a maintainer will misunderstand your intentions is high.
Enforcement: This rule shall be enforced during code reviews.