I have a question about memcpy that I hope someone can answer. Here's a short demonstrative program:
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main (开发者_如何学Pythonint argc, char **argv){
unsigned char buffer[10];
unsigned short checksum = 0x1234;
int i;
memset(buffer, 0x00, 10);
memcpy(buffer, (const unsigned char*)&checksum, 2);
for(i = 0; i < 10; i ++){
printf("%02x",buffer[i]);
}
printf("\n");
return 0;
}
When I run this program, I get 34120000000000000000.
My question is why don't I get 12340000000000000000?Thanks so much
You are getting 34120000000000000000 because you are on a little-endian system. You would get 12340000000000000000 on a big-endian system. Endianness gives a full discussion of big-endian vs. little-endian systems.
little endian/big endian architecture ? which mean that 2 byte of checksum is inverted.
It is just a guess, if my answer is not true Comment it and I will delete it.
Intel's CPUs are little endian, they store numbers little word first
This is apparently evidence that Intel don't do inhouse drug testing.
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