Function declared in block¶

ID: cpp/function-in-block
Kind: problem
Security severity: 
Severity: recommendation
Precision: very-high
Tags:
   - maintainability
   - readability
   - external/jsf
Query suites:
   - cpp-security-and-quality.qls

Click to see the query in the CodeQL repository

This rule finds functions that are declared in a block. It is confusing to declare a function at block scope, and the visibility of the function is not what would be expected. extern function declarations inside a block, which are allowed in C, are particularly confusing, as the scope of the declaration is the entire file, not just the block where it was declared.

int f() {
	extern int other(); //scope of externs is the entire file, not just the 
	                    //block where it is declared
	...
	other()
}

int g() {
	other(); //this will use the other() function declared inside f()
}