c - Valgrind 不喜欢我的 realloc()？

Question

uint32_t * newArr = realloc( myStruct->arr, 2 * muStruct->Capacity * sizeof(myStruct->arr) )

if (newArr == null)
{
    free(myStruct->arr);
    return false;
}
else
{
    myStruct->arr = newArr;
    myStruct->Capacity *= 2;
    ...

Valgrind 对此说道:

Address 0x51f7c80 is 0 bytes after a block size of 80 alloc'd
    at 0x4C2BB78: realloc (vg_replace malloc.c:785)

这是怎么回事？这是我的 newArr == null 情况吗？

Answer 1

该错误表明您在某处读取(或写入)超出了数组的范围，如 valgrind article concerning debugging of memory problems 中所述。 :

sample2.c: As you can see from the output in Figure Two, references to element 513 in the two arrays cause a write error, a read error, and another write error. The message Address 0x40CA0224 is 0 bytes after a block of size 512 alloc'd indicates that there is no storage beyond the end of the array of 512 bytes.

这可能是您程序中的其他地方。语句 if (newArr == null) ... free(myStruct->arr) 是正确的恕我直言。