C ++结构访问冲突

Question

I have the following struct defined in the header file:

typedef struct _wfs_cdm_physicalcu
{
    LPSTR           lpPhysicalPositionName;
    CHAR            cUnitID[5];
    ULONG           ulInitialCount;
    ULONG           ulCount;
    ULONG           ulRejectCount;
    ULONG           ulMaximum;
    USHORT          usPStatus;
    BOOL            bHardwareSensor;
} WFSCDMPHCU, * LPWFSCDMPHCU;

And in my code file I try to use it like this:

LPWFSCDMPHCU cdm_physical_cass;
strcpy(cdm_physical_cass->cUnitID, "1234");
cdm_physical_cass->lpPhysicalPositionName = "DISP1";
cdm_physical_cass->bHardwareSensor = FALSE;
cdm_physical_cass->ulInitialCount = 100;

The code compiles fine, however I get access violation on that strcpy so I think the struct is not initialized properly. Any thoughts?

Answer 1

cdm_physical_cass is not initialized/allocated. You have to call

LPWFSCDMPHCU cdm_physical_cass = new WFSCDMPHCU;

Better would be to use smart pointers (as std::unique_ptr ).

Answer 2

LPWFSCDMPHCU cdm_physical_cass; is not a struct it's a pointer to a struct of type WFSCDMPHCU . You must allocate memory for the struct pointed to by cdm_physical_cass . The function WFMAllocateBuffer is recommended for that.

Answer 3

由于LPWFSCDMPHCU是指针而不是struct，因此您需要为该指针（LPWFSCDMPHCU）分配内存（取决于语言，为malloc或new），然后可以使用这些字段。