The CERT ® C Coding Standard: 98 Rules for Developing Safe, Reliable, and Secure Systems, Second Edition

Chapter 12. Error Handling (ERR)

Chapter Contents

Risk Assessment Summary

ERR30-C. Set errno to zero before calling a library function known to set errno, and check errno only after the function returns a value indicating failure

The value of errno is initialized to zero at program startup, but it is never subsequently set to zero by any C standard library function. The value of errno may be set to nonzero by a C standard library function call ...