c - Getting an "implicit declaration of function" error in Code Blocks -

i still quite new c, , keep getting error in code blocks stops me running programs. error "implicit declaration of functions printf_s() , scanf_s(). here code:

#define __stdc_want_lib_ext1__ 1 #include <stdio.h>  int main(void) {   int age = 0;   char name[20];    printf_s("enter age: ");   scanf_s("%d", &age);    print_s("enter name: ");   scanf_s("%s", name, sizeof(name));    printf_s("your name %s , %d years old.\n", name, age);    return 0; } 

printf_s , scanf_s available if __stdc_lib_ext1__ defined library implementation. added since c11 standard.

first have check __stdc_lib_ext1__ defined or not, should use printf_s or scanf_s.

#define __stdc_want_lib_ext1__ 1 #include <stdio.h> int main(void) {   int age = 0;   char name[20];   #ifdef __stdc_lib_ext1__       printf_s("enter age: ");       scanf_s("%d", &age);       print_s("enter name: ");       scanf_s("%s", name, sizeof(name));       printf_s("your name %s , %d years old.\n", name, age);   #else       printf("enter age: ");       scanf("%d", &age);       print("enter name: ");       scanf("%19s", name);       printf("your name %s , %d years old.\n", name, age);   #endif   return 0; }