fstream & file sharing: How to do what you used to be able to do?

[kberson]

With .Net 2003, fstream.h disappeared and the open command went from three parameters to two.

How do I now open a file and deny other applications from accessing the file until I am done writing to it? I used to be able to do:

fstream outf("somefile.txt",ios::app,filebuf::sh_none);  

Is there another way to do this, or am I out of luck?

[2big]

the fstream change was one of the hardest changes in .NET for me, as I use a lot of functionality from it.

Try this:

#include <fstream>
using namespace std;

int main() {
ofstream test  //Initiate "test" handle
test.open("somefile.txt",ios::app,filebuf,sh_none);  //Open File
test << "Line Written to file";   //Write to file
test.close()  //Close handle
return 0;
}

[kberson]

#include <fstream>
using namespace std;

int main() {
ofstream test  //Initiate "test" handle
test.open("somefile.txt",ios::app,filebuf,sh_none);  //Open File
test << "Line Written to file";   //Write to file
test.close()  //Close handle
return 0;
}

Are you sure of this code? I get a compile error:

error C2065: 'sh_none' : undeclared
error C2275: 'std::filebuf' : illegal use of this type as an expression.

[kberson]

hmmm... the include didn't come out, but it should be there

[weavercs]

>Are you sure of this code? I get a compile error:

>error C2065: 'sh_none' : undeclared
>error C2275: 'std::filebuf' : illegal use of this type as an expression.

You should use: filebuf.sh_none if it doesn't accept sh_none.

[kberson]

That wouldn't compile either:

error C2039: 'sh_none' : is not a member of 'std::basic_filebuf<_Elem,_Traits>'

Here's a simple example --

#include "stdafx.h"
#include <fstream>
#include "example.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

using namespace std;

CWinApp theApp;

int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{
	int nRetCode = 0;

	if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0))
	{
		nRetCode = 1;
	}
	else
	{
		ofstream outf("test.txt",ios::out,filebuf.sh_none);
	}

	return nRetCode;
}