Determine CPU Endianness at Runtime

by Bramante - - | Comments

之前工作上用的CPU由Big Endian改成了Little Endian, 同樣的code會在不同Endian的CPU上跑, 因此寫了段能在runtime偵測Endian的code, 這樣可以用來偵測程式跑在哪個Chip上.

endianness.c
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#include <stdio.h>

int main(void)
{
 unsigned int a = 1 ;
 unsigned char *ptr ;
 ptr = (unsigned char *)&a ;
 if(ptr[0]==0)
   {
    printf("big endian\n");  
   }
  else
   {
    printf("little endian\n");   
   }
 return 0 ;
}

Terminal
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bramante@matrix:~/endianness$ gcc -o endianness endianness.c
bramante@matrix:~/endianness$ ./endianness
little endian
bramante@matrix:~/endianness$

Comments