How to convert double to BSTR

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C++

Want to assign a double value to BSTR string.
Are there any macros /functions for this

Posted 25-Aug-11 23:44pm

explorerC

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4 solutions

Solution 4

1、use _gcvt to convert double to char*
2、(BSTR)(CString)your char* var

Posted 30-Aug-11 17:28pm

buyong

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Member 12726815 8-Mar-18 18:32pm

is curious the sample code in solution 1.

prints me a memory address, example:
I add a cout << myvarbstr << end;

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CPallini · Accepted Answer · 2011-08-26T00:04:00

You may just represent a double value with a BSTR, for instance

C++

#include <windows.h>
#include <tchar.h>
#include <sstream>
using namespace std;

int main()
{
  wostringstream wos;
  double d = 0.57;
  wos << d;
  BSTR bstr = SysAllocString(wos.str().c_str());
  // enjoy with bstr
  // ...
  SysFreeString(bstr);
}

xuragan · Accepted Answer · 2011-08-30T12:01:00

C++

#include "windows.h"
#include "comutil.h"

void your_func(BSTR bstr);

int main()
{
   _bstr_t str(_variant_t(double(123.456)));
   
   // str is castable to BSTR
   // use it like this

   your_func(str);

   // or simply
   your_func(_bstr_t(_variant_t(double(123.456))));
   
   return 0;
}

Espen Harlinn · Accepted Answer · 2011-08-30T12:45:00

Solution 3

Why not use VarBstrFromR8[^] Windows API?

There are many other Data Type Conversion Functions[^] provided with Windows too.

Best regards
Espen Harlinn

Posted 30-Aug-11 12:45pm

Espen Harlinn

Comments

Sergey Alexandrovich Kryukov 6-Sep-11 20:03pm

My 5.
--SA

Espen Harlinn 7-Sep-11 4:49am

Thanks Sergey!

How to convert double to BSTR

4 solutions

Solution 1

Solution 2

Solution 3

Solution 4

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