Yes, it is generally good practice to always cast the return value of functions to (void) if not used. This is self-documenting code showing that you aren't using the return value on purpose and did not just forget it by accident.

For reference, either using the return value or casting it to void is enforced by MISRA-C (17.7) and other coding quality standards.

Hosted system compilers generally don't warn out of tradition, because that would mean that we'd have to write (void) printf("hello world"); and similar when using common functions, where the result is not commonly used. This whole sloppiness goes all the way back to the first K&R book. Which is a shame really, since in the case of scanf etc, it is definitely good practice to always check the result.

Codewarrior is more pedantic than hosted system compilers, because it is intended to be exclusively used for embedded systems and you aren't as likely to use stdio.h and similar libs there. Similarly, Codewarrior is intended to be suitable for automotive systems, where quality standards are much higher than those for PC programming.

This has nothing to do with C90 as such.

posted over 3 years ago

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Lundin‭

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