# error directive in c

Syntax : #error



If compiler compiles this line then it shows a compiler fatal error i.e it only issue an error message and this error message includes . i.e it only issue an error message and this error message includes .

Example :




#include

#ifndef __MATH_H

#error First include then compile

#else

int main(){

float a,b=25;

a=sqrt(b);

printf("%f",a);