DCL41-C. Do not refer to a static object in an external inline function

The C Standard, subclause 6.7.4 paragraph 3, says:

An inline definition of a function with external linkage shall not contain a definition of a modifiable object with static or thread storage duration, and shall not contain a reference to an identifier with internal linkage.

Noncompliant Code Example

This code refers to a static variable, which has internal linkage, inside an external inline function:

static int I = 12;
extern inline void func(int a) {
  int b = a * I;
  /* ... */
}

Compliant Solution

This compliant solution does not declare the variable at file scope to be static and so the variable has external linkage by default.

int I = 12;
extern inline void func(int a) {
  int b = a * I;
  /* ... */
}

 Risk Assessment

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

Bibliography