Data serialization in C?

Question

I have this structure which I want to write to a file:

typedef struct
{
    char* egg;
    unsigned long sausage;
    long bacon;
    double spam;
} order;
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Answer 1

The C standard doesn't define a representation for floating point types. Your best bet would be to convert them to IEEE-754 format and store them that way. Portability of binary serialization of double/float type in C++ may help you there.

Note that the C standard also doesn't specify a format for integers. While most computers you're likely to encounter will use a normal two's-complement representation with only endianness to be concerned about, it's also possible they would use a one's-complement or sign-magnitude representation, and both signed and unsigned ints may contain padding bits that don't contribute to the value.