主题：【贴图】最近看的一些令人蛋疼的好图（四） -- 李根

觉得应该是参数传给printf之前就被做了类型转换成int了（此处应该是把给定参数的最高位重复以达到占满32bit int型），printf里头应该是直接在高位补0？printf这没跟进去看，因为汇编也忘的差不多了，不过重复了好几遍，结果都是稳定的，应该printf内部从int到long int不是越界读的结果。

gcc 4.2.4 x86_64-linux-gnu

int main () {

/*

int i=1;

int j=(1<<31)+255;

char *c_ip = &j;

printf("int len is %d\n",sizeof(i));

printf("long int len is %d\n",sizeof(j));

printf("int pointer len is %d\n",sizeof(&i));

printf("int is %x\n",j);

printf("long int j is %llx\n",j);

printf("long int char pointer is %llx\n",*c_ip);*/

int a=-1;

printf("long int a is %llx\n",a);

int b=255;

printf("long int b is %llx\n",b);

char c=128;

printf("long int c is %llx\n",c);

char d=127;

printf("long int d is %llx\n",d);

char f=128;

printf("long int f is %llx\n",(int)f);

char g=127;

printf("long int f is %llx\n",(int)g);

printf("long int -1 is %llx\n",(long int)-1);

return 0;

}

output：

long int a is ffffffff

long int b is ff

long int c is ffffff80

long int d is 7f

long int f is ffffff80

long int f is 7f

long int -1 is ffffffffffffffff