How Can I Correctly Use strtol to Convert Strings to Long Integers and Handle Potential Errors?

Correct Usage of strtol

The strtol function converts a string representation of a long integer to a long value. However, it is essential to understand how to handle errors correctly when using this function.

In the given code, the problem arises due to an incorrect assumption. The code relies on the fact that if strtol successfully converts the string, the second parameter should be equal to NULL. However, this assumption may not always hold true.

To effectively detect errors from strtol, it is necessary to follow the proper error handling guidelines:

• Set errno to 0 before calling strtol: Standard library functions do not set errno to 0, so it should be manually set to zero before each strtol call.
• Check temp against both str and *temp != '

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