When the return value of a function call contains the operation status code, this value should be tested to make sure the operation completed successfully.

This rule raises an issue when the return values of the following are ignored:

Noncompliant Code Example

public void doSomething(File file, Lock lock) {
  file.delete();  // Noncompliant
  // ...
  lock.tryLock(); // Noncompliant
}

Compliant Solution

public void doSomething(File file, Lock lock) {
  if (!lock.tryLock()) {
    // lock failed; take appropriate action
  }
  if (!file.delete()) {
    // file delete failed; take appropriate action
  }
}

See