Thread: 128 bit (long double) printf not working

I have run the following code to see what my computer's byte size is for each data type:

Code:

#include <stdio.h>
#include <limits.h>

int main()
{
    printf("The size of char in bytes is: %llu.", sizeof(char));
    printf("\nThe size of short in bytes is: %llu.", sizeof(short));
    printf("\nThe size of int in bytes is: %llu.", sizeof(int));
    printf("\nThe size of long in bytes is: %llu.", sizeof(long));
    printf("\nThe size of long long in bytes is: %llu.", sizeof(long long));
    printf("\nThe size of float in bytes is: %llu.", sizeof(float));
    printf("\nThe size of double in bytes is: %llu.", sizeof(double));
    printf("\nThe size of long double in bytes is: %llu.", sizeof(long double));
    
    return 0;
}

However, when I try to use printf for long double, it always prints the same junk exponent value regardless of what the variable is set to in the program.

Code:

#include <stdio.h>

int main()
{
    long double x = 3.1415;

    printf("%Lg", x);
    
    return 0;
}

I have read on the internet forums that this is either a printf limitation or a compiler issue or some combination of these. I am using a MinGW GCC 6.1.0 compiler on a 64-bit Windows PC.

How do I fix this? Do I need to get a different compiler or is there another C function that can print this 16-bit (or 20-bit) long double properly?