用Python打包和用C解包

Question

I'm trying to pack integers as bytes in python and unpack them in C. So in my python code I have something like

testlib = ctypes.CDLL('/something.so')
testlib.process(repr(pack('B',10)))

which packs 10 as a byte and calls the function "process" in my C code.

What do I need in my C code to unpack this packed data? That is, what do I need to do to get 10 back from the given packed data.

Answer 1

Assuming you have a 10 byte string containing 10 integers, just copy the data.

char packed_data[10];
int unpacked[10];

int i;
for(i = 0; i < 10; ++i)
    unpacked[i] = packed_data[i];

... or using memcpy

On the other hand, if you're using 4 bytes pr int when packing, you can split the char string in C and use atoi on it. How are you exchanging data from Python to C ?