了解在共享库中重载operator new的行为

我正在Centos平台上工作一个共享库和应用程序[clang，llvm3.9.0和libc]，并且库和应用程序都会重载它们自己的operator new和operator delete .

除1例外，一切正常 . 在调用std :: string的copy构造函数时总是调用应用程序端的 operator new ：

这是senario：

std::string str1 ( "A very strange issue on CentOS using clang and libc++" ); //operator new of library side called.

std::string str2(str1); //operator new of application side called. WHY??

对于库侧调用两种情况下的operator delete .

以下是运行以下代码时的日志：

====================================================
operator new in shared library
operator new called Application side
operator delete in shared library
operator delete in shared library
====================================================

共享库侧操作员new和delete：

void * operator new ( size_t len ) throw ( std::bad_alloc )
    {
        printf("operator new in shared library\n");
        void * mem = malloc( len );
        if ( (mem == 0) && (len != 0) ) throw std::bad_alloc();
        return mem;
    }

    void * operator new[] ( size_t len ) throw ( std::bad_alloc )
    {
        printf("operator new[] in shared library\n");
        void * mem = malloc( len );
        if ( (mem == 0) && (len != 0) ) throw std::bad_alloc();
        return mem;
    }

    void operator delete ( void * ptr ) throw()
    {
        printf("operator delete in shared library\n");
        if ( ptr != 0 ) free ( ptr );
    }

    void operator delete[] ( void * ptr ) throw()
    {
        printf("operator delete[] in shared library\n");
        if ( ptr != 0 ) free ( ptr );
    }

应用程序端操作员new和operator delete：

void * operator new ( size_t len ) throw ( std::bad_alloc )
{
    void * mem = malloc ( len );
    printf("operator new called Application side\n");
    if ( (mem == 0) && (len != 0) ) throw std::bad_alloc();
        return mem;
}

void * operator new[] ( size_t len ) throw ( std::bad_alloc )
{
    void * mem = malloc ( len );
    printf("operator new[] called Application side\n");
    if ( (mem == 0) && (len != 0) ) throw std::bad_alloc();
        return mem;
}

void operator delete ( void * ptr ) throw()
{
    printf("operator delete[] called Application side\n");
    if ( ptr != 0 )free ( ptr );
}

void operator delete[] ( void * ptr ) throw()
{
    printf("operator delete[] called Application side\n");
    if ( ptr != 0 ) free ( ptr );
}

请帮忙 .