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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:

  1. 为什么 print (uintptr_t )(0x650408) 显示垃圾数据?
  2. 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!?!)
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