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.
I’m learning C and hope someone can explain what’s the logic of using #ifndef?
I also find many C programs I looked, people seems following a convention using the filename following the #ifndef, #define and #endif. Is there any rule or tip on how to choose this name?
#ifndef BITSTREAM_H
#define BITSTREAM_H
#include <stdio.h>
#include <stdint.h>
/*Some functions*/
#endif
The term for what you’re looking for is Preprocessor Directives.
#ifndefdoesn’t need to be followed by a filename, for example it’s common to see#ifdef WINDOWSor#ifndef WINDOWS, etc.