Shared Memory Writing

[velayudhan_raj]

Hi Guys, A structure,which consists of member variables ( eg: int, float data type ) is written in a shared memory from a BackEnd application, which is accessed by a Front End application. When I try to write a Cstring variable or TCHAR array as member variable of the structure, it is not working, and exception occurs. Actually my need is to write a string to shared memory - from Back end, which is accessed by Front End. The string should be a member of this structure. So plz help me what datatype to be used. Thanks in Advance Velayudhan

[Laxman Auti]

velayudhan_raj wrote:

A structure,which consists of member variables ( eg: int, float data type ) is written in a shared memory from a BackEnd application, which is accessed by a Front End application. When I try to write a Cstring variable or TCHAR array as member variable of the structure, it is not working, and exception occurs. Actually my need is to write a string to shared memory - from Back end, which is accessed by Front End. The string should be a member of this structure. So plz help me what datatype to be used.

Try Char* instead.:) Knock out 't' from can't, You can if you think you can :cool:

[velayudhan_raj]

Actually I am working in Unicode support application. so I tried with TCHAR* , but it is not working. A doubt : CString can't be written in Shared memory, as we cannot define the size of CString , Is it correct?

[Viorel]

A possible solution is to define a fixed-size array within your shared structure, for instance: TCHAR mName[100]. The size of the array must be large enough. Now for string-transfer operations use string-manipulation functions like strcpy in non-Unicode or wcscpy in Unicode mode. (If you use lstrcpy or StrCpy, then they will work in both modes). Unfortunately, this is problematic to use if you cannot predict and limit the largest size of your string.

[Hamid Taebi]

See Here[^] maybe it is some helpful to you_**

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whitesky

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[ThatsAlok]

velayudhan_raj wrote:

Actually I am working in Unicode support application. so I tried with TCHAR* , but it is not working.

Give Specfic Size to the String Member, i.e. USE TCHAR youObj[100];

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[James R Twine]

If the two applications are complete separate processes, you cannot just share pointers between the two of them.  If the shared memory segment is coherent between both processes, you can simply use a portion of it as a buffer for text/string data.  You can then pass offsets into the buffer to specify data locations.    Or, you can change the structure to contain a proper array and copy the entire structure to the shared memory area:

struct sMyData
{
    double m_dValue;
    char   m_cValue;
    char   m_caValue[ 128 ];
    int    m_iValue;
};

When moving data between processes via some kind of shared memory implementation, you should generally avoid pointers and "real" objects.    Peace! -=- James

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