V747. An odd expression inside parenthesis. It is possible that a function name is missing.

The analyzer detected a suspicious expression in parentheses consisting of various variables and values separated by commas. However, it doesn't look like the comma operators ',' are used to reduce the code.

Consider the following example:

if (memcmp(a, b, c) < 0 && (x, y, z) < 0)

When writing the program, the author forgot to write the function name, 'memcmp'. However, the code still compiles successfully, although it doesn't work as intended. In the right part, executing two comma operators results in variable 'z'. It is this variable that is compared with zero. So, this code turns out to be equivalent to the following:

if (memcmp(a, b, c) < 0 && z < 0)

Correct code:

if (memcmp(a, b, c) < 0 && memcmp(x, y, z) < 0)

Note. Sometimes, the ',' operator is used to reduce code. That's why the analyzer doesn't always output the warning about commas inside parentheses. For example, it treats the following code as correct:

if (((std::cin >> A), A) && .....)

We do not recommend writing complex expressions like this because it is going to make it difficult for your colleagues to read such code. But there is no apparent error either. It's just that the developer wanted to combine the operations of retrieving a value and checking it in one expression.

Here's another similar example:

if (a)
  return (b = foo(), fooo(b), b);

This diagnostic is classified as:

Bugs Found

Checked Projects
Collected Errors
14 279
This website uses cookies and other technology to provide you a more personalized experience. By continuing the view of our web-pages you accept the terms of using these files. If you don't want your personal data to be processed, please, leave this site. Learn More →