c++写日志文件的操作

class LogFile
{
public:
static LogFile &instance();
operator FILE *() const { return m_file; }
private:
LogFile(const char *filename)
{
m_file = fopen(filename, "a+");
}
~LogFile()
{
fclose(m_file);
}
FILE *m_file;
};

LogFile &LogFile::instance()
{
static LogFile log("AppLog.txt");
return log;
}

//用的时候可以这么写：
fwrite("abc", 1, 3, LogFile::instance());