我有一个奇怪的内存错误。
代码很简单:
void *to = calloc(2, sizeof(uint64_t));
...
int add_symbol_to_symbol(void *from, void *to) {
uintptr_t *fromSymbol;
uintptr_t *toSymbol;
uint64_t i;
fromSymbol = (uintptr_t*) from;
toSymbol = (uintptr_t*) to;
for (i = 0; i < 2; i++)
{
*toSymbol ^= *fromSymbol;
toSymbol++;
fromSymbol++;
}
return 0;
}
当我调试代码并打印出内存的地址和该内存的值时,我可以看到在异或发生之前 toSymbol 在其内存中具有非零值......但这取决于我如何打印出数据.
数据库:
print toSymbol
$21 = (uintptr_t *) 0x650400
(gdb) print (toSymbol+1)
$23 = (uintptr_t *) 0x650408
(gdb) print *(toSymbol)
$25 = 0
(gdb) print *(toSymbol+1)
$24 = 4575657221408423936
(gdb) print *(unsigned long long)(toSymbol+1)
$26 = 0
(gdb) print *(unsigned long long*)(toSymbol+1)
$27 = 4575657221408423936
print *(uintptr_t*)(0x650408)
$30 = 4575657221408423936
(gdb) print *(uintptr_t)(0x650408)
$31 = 0
所以我的问题:
- 为什么 print (uintptr_t )(0x650408) 显示垃圾数据?
- 为什么 print *(uintptr)(0x650408) 显示零?(即,为什么将 64 位十六进制地址转换为 64 位值而不是 64 位地址会改变任何东西!?!)