C #error in C Language
Categories: C language
The #error preprocessor directive indicates error. The compiler gives fatal error if #error directive is found and skips further compilation process.
C #error example
Let's see a simple example to use #error preprocessor directive.
#include<stdio.h>
#ifndef __MATH_H
#error First include then compile
#else
void main(){
float a;
a=sqrt(7);
printf("%f",a);
}
#endif
Output:
Compile Time Error: First include then compile
#include<stdio.h>
#include<math.h>
#ifndef __MATH_H
#error First include then compile
#else
void main(){
float a;
a=sqrt(7);
printf("%f",a);
}
#endif
Output:
2.645751