The header <errno.h> defines several macros, all relating to the reporting of error conditions

#define _CRT_SECURE_NO_WARNINGS#include 
     
      #include 
      
       #include 
       
        #include 
        
         int main(int argc, char *argv[]){    sqrt(-1.0);    printf("%d %s\n", errno, strerror(errno));    return 0;}