Question

hi i am returning a LPTSTR type of object from unmanaged code which essentially points to a string . i am in managed code now and i m unable to read it in C# . the string being returned is just “YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY”..

Here is my managed code snippet.

[DllImport("TableConfig.dll", EntryPoint = "?getTableConfigDlg@@QAEPA_WXZ", CharSet = CharSet.Ansi)]
        static extern String getColumnNamesFormat();

Is there anything wrong with this ???
How do i get meaningful data out of the string being returned from unmanaged code ?

Thanks

Native Code:-

for(int i=0; i<numCols; ++i)
{
    const bet_TableConfigColumn *col_p = tc_p->getColumn(i);
    const char* colName = tc_p->getKeyName(i);
    const char* colFormat = col_p->getFormat();
    str+=",";
    str+=colName;
    cout << "Col Name" << colName << "Format: " << colFormat;

} // end of for(i)
         LPTSTR pString=str.GetBuffer(0);
            str.ReleaseBuffer();
      return pString;

Answer 1

Managed:

DllImport("TableConfig.dll", EntryPoint = "?getTableConfigDlg@@QAEPA_WXZ")]
static extern void getColumnNamesFormat( StringBuilder tableNames );

StringBuilder result = new StringBuilder( 255 );
getColumnNamesFormat( result );

Native:

change method signature to return void, take in a LPTSTR for the managed buffer.

_tcscpy(managedBuffer, str);