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How to read c++ structure binary file in excel vba

Posted by: admin April 23, 2020 Leave a comment

Questions:

I have a c++ generated structure file that contains the corresponding struct in binary form:

struct userinfo
{
   char username[200];
   char Password[200];
   char Genkey[200];
   long UniqueKey;
};

How can I read this file in Excel VBA code?

How to&Answers:

This should get you somewhere:

Option Explicit

Type userinfo
    username As String * 200
    Password As String * 200
    Genkey As String * 200
    UniqueKey As Long
End Type

Sub readbin()
    Dim rec As userinfo
    Dim intFileNum As Integer
    intFileNum = FreeFile
    Open "C:\Temp\my.bin" For Binary Access Read As intFileNum
    Do While Not EOF(intFileNum)
        Get intFileNum, , rec
        Debug.Print "->", rec.UniqueKey, rec.username
        Debug.Print , rec.Password
        Debug.Print , rec.Genkey
    Loop
    Close intFileNum
End Sub

Further notes: C++ padding is not standardized, and is a pain when interfacing with other languages. The best way to deal with C++ padding is to remove it so it to become language neutral. This can be done by redefining C++ to:

#pragma pack (push, 1)
struct userinfo
{
   char username[200];
   char Password[200];
   char Genkey[200];
   long UniqueKey;
};
#pragma pack (pop)

Although if you can’t modify the source program, then you might need to look around for other options.