Problems transforming QString to _bstr_t

musimbate

Hi,
I am trying to transform a QString to _bstr_t type as follows:

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QString mFilename="C:/agatebo/amahoro.doc";

QByteArray srcBa1 = mFilename.toLocal8Bit();
const char *srcString1 = srcBa1.data();
CString myStringSrc(srcString1,srcBa1.size());

BSTR bstrUser = myStringSrc.AllocSysString();

_bstr_t user(bstrUser,TRUE);

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but when I pass the _bstr_t I get to this function:

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pdfObject->cPrintFile(user);

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PDFCreator ,a program whose COM interface I am using just crashes .I suspect this has something to do with unicode but can't figure out what yet.I should mention that when I directly pass a path to the file like this:

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pdfObject->cPrintFile(L"c:\agatebo\amahoro.doc");

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all is ok ,I simply want to be able to use QStrings that come from other modules of my Qt application.I am compiling with Qt 4.8 msvc2010 if this matters. I would appreciate any help on this.

Rondog

It probably is related to how the BSTR is created (possibly the type; char vs wchar_t). I do this with the following:

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// char_buffer is a block of memory
// char_buffer is zero'd prior to use (not shown)

input_string.toWCharArray(char_buffer);
bstr_val = SysAllocString(char_buffer);
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If you call a function that returns BSTR you are responsible to free the memory associated with the variable.

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bstr = some_com_function_that_returns_BSTR();

QString return_string(QString::fromWCharArray(bstr,lstrlen(bstr)));
SysFreeString(bstr);

return return_string;
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