#ifndef NULL
#define NULL NULL
#endif
This code compiles in gcc with no warnings/errors. Can someone explain what the preprocessor is doing here?
#ifndef NULL #define NULL NULL #endif This code compiles in gcc with no warnings/errors.
Share
Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
#ifndef NULL
#define NULL NULL
#endif
This code compiles in gcc with no warnings/errors. Can someone explain what the preprocessor is doing here?
Anywhere the compiler sees the text “NULL” it will replace it with the text “NULL”. It’s like doing a search-and-replace in your code for “NULL” and replacing with “NULL”. Not illegal, just weird 🙂