c++ - Valgrind 在 fclose() 处检测到内存泄漏

Question

为什么 valgrind 说我在调用 fclose() 时有内存泄漏？

#include <stdio.h>

class Stream
{
    public:
        Stream();
        ~Stream();
    private:
        char*  pszOutput;
        size_t size;
        FILE* file;
};

Stream::Stream()
{
    file = open_memstream(&pszOutput, &size);
}

Stream::~Stream()
{
    fclose(file);
}

int main()
{
    Stream s;   

    return 0;
}

Valgrind 报告:

==52387== 1 bytes in 1 blocks are definitely lost in loss record 1 of 1
==52387==    at 0x4C28CCE: realloc (vg_replace_malloc.c:632)
==52387==    by 0x5639CA3: _IO_mem_finish (memstream.c:132)
==52387==    by 0x5635956: fclose@@GLIBC_2.2.5 (iofclose.c:66)

初始化 pszOutput 或 size 重要吗？还是我需要添加其他内容？

Answer 1

发件人:http://linux.die.net/man/3/open_memstream

The open_memstream() function opens a stream for writing to a buffer. The buffer is dynamically allocated (as with malloc(3)), and automatically grows as required. After closing the stream, the caller should free(3) this buffer.

因此，根据这个，您需要在文件描述符关闭后释放(pszOutput)。