c++ - posix_memalign 内存分配和内存释放

Question

在下面的代码中，是否需要释放allocated_memory2和allocated_memory3？你认为这段代码没有内存泄漏吗？

class data {
public:
    data();
    ~data();
    unsigned char *allocated_memory1;  
    unsigned char *allocated_memory2;  
    unsigned char *allocated_memory3;  
};

data::data() {
    posix_memalign((void **) &allocated_memory1, 16, 1040);
    memset(allocated_memory1, 0, 1040);

    allocated_memory2 = allocated_memory1 + 4;
    allocated_memory3 = allocated_memory1 + 16;
}

data::~data() {
    free(allocated_memory3);
    free(allocated_memory2);
    free(allocated_memory1);
}

Answer 1

仅释放 allocated_memory1(由 posix_memalign 调用分配)就足够/正确了。 allocated_memory2 和 allocated_memory3 只是指向同一内存块不同部分的指针。所以释放它们是不正确的。

您可以避免直接公开 allocated_memory1 指针 - 万一它被更改，您可能无法释放它。你可以使用:

class data {

private:
    unsigned char *allocated_block;

public:
    data();
    ~data();
    unsigned char *allocated_memory1;  
    unsigned char *allocated_memory2;  
    unsigned char *allocated_memory3;  
};

data::data() {
    posix_memalign((void **) &allocated_block, 16, 1040);
    memset(allocated_block, 0, 1040);

    allocated_memory1 = allocated_block + 4;
    allocated_memory2 = allocated_block + 4;
    allocated_memory3 = allocated_block + 16;
}

data::~data() {
    free(allocated_block);
}