c++ - 错误 : request for member (maybe you meant to use '->' ? ) 已经使用 '->'

Question

对于此错误的含义是否有简单的解释？

error: request for member 'Attributes' in '* printerInfo', which is of pointer type 'PPRINTER_INFO_2 {aka _PRINTER_INFO_2A*}' (maybe you meant to use '->' ?)

PPRINTER_INFO_2* printerInfo = NULL;

    void ChangedPrinter()
    {
       ...
       DWORD attributesPrinterInfo;

       printerInfo = (PPRINTER_INFO_2*) malloc(bufferSize);

       attributesPrinterInfo = printerInfo->Attributes; // error

       free(printerInfo);
    }

我做错了什么？？？

Answer 1

PRINTER_INFO_2结构定义为:

typedef struct _PRINTER_INFO_2 {
  // ...
} PRINTER_INFO_2, *PPRINTER_INFO_2;

所以 PPRINTER_INFO_2 是指向 PRINTER_INFO_2 的指针。当你做的时候

printerInfo = (PPRINTER_INFO_2*) malloc(bufferSize);

printerInfo 实际上变成了指向 PRINTER_INFO_2 的指针。我不确定这是故意的还是只是一个错误，但如果它是 PPRINTER_INFO_2* 那么正确的用法是:

(*printerInfo)->Attributes