Peek raw data from structure/type in C++.

bits_peeker.cc

#include <cstdio>

template<typename T>
struct _bits_peeker {
    union {
        unsigned char bytes[sizeof(T)];
        T             value;
    };
};
#define bits_peeker struct _bits_peeker

#define dump(D) { \
    puts("In Hex:"); \
    for (int i = 0; i < sizeof(D.value); i++) { \
        printf("%.2X ", D.bytes[i]); \
    } \
    puts(""); \
    puts("In Bits:"); \
    for (int i = 0; i < sizeof(D.value); i++) { \
        for (int j = 8; j >= 0; j--) { \
            printf("%d", (D.bytes[i] & (1 << j)) >> j); \
        } \
        printf(" "); \
    } \
}

int main () {
    bits_peeker<double> peeker;
    peeker.value = 123.456789;
    printf("Value = %lf\n\n", peeker.value);
    dump(peeker);
    return 0;
}