How to turn a hex string into an unsigned char array?

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This answers the original question, which asked for a C++ solution.

You can use an istringstream with the hex manipulator:

std::string hex_chars("E8 48 D8 FF FF 8B 0D");

std::istringstream hex_chars_stream(hex_chars);
std::vector<unsigned char> bytes;

unsigned int c;
while (hex_chars_stream >> std::hex >> c)
{
    bytes.push_back(c);
}

Note that c must be an int (or long, or some other integer type), not a char; if it is a char (or unsigned char), the wrong >> overload will be called and individual characters will be extracted from the string, not hexadecimal integer strings.

Additional error checking to ensure that the extracted value fits within a char would be a good idea.

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