ios::nocreate and the latest standard

This is a discussion on ios::nocreate and the latest standard within the C++ Programming forums, part of the General Programming Boards category; ios::nocreate was removed in the latest standard, for some reason. Without it, how do I open a file (for reading) ...

  1. #1
    Confused Magos's Avatar
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    ios::nocreate and the latest standard

    ios::nocreate was removed in the latest standard, for some reason. Without it, how do I open a file (for reading) ONLY if it exists? I read in some other post here that the file shouldn't be opened if it doesn't exists, but mine still does.

    Code:
    ifstream ReadFile;
    
    ReadFile.open(FileName, ios::in); //I want ot add ios::nocreate here too...
    if(ReadFile.fail())
    {
       //Never reached, even though the file doesn't exists
       return 0;
    }
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  2. #2
    Cat
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    Your implementation is noncompliant; a conforming compiler will enter your error handler. Upgrade your compiler, I guess.

    Assuming "notareal.fil" does not exist, the following should print "Failure." on any conforming compiler:

    Code:
    #include <iostream>
    #include <fstream>
    
    int main(){
    
    	std::ifstream ReadFile;
    
    	ReadFile.open("c:\\notareal.fil", std::ios::in);
    	if(ReadFile.fail())
    		std::cout << "Failure." << std::endl;
    	else std::cout << "Success." << std::endl;
    }
    Last edited by Cat; 12-06-2003 at 04:43 PM.
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  3. #3
    Confused Magos's Avatar
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    I'm using Visual C/C++ v6.?
    I thought that would be new enough...
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  4. #4
    and the hat of wrongness Salem's Avatar
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    > I'm using Visual C/C++ v6.?
    v6 is especially poor at complying to any C++ standards
    The latest .net c++ compiler is much better
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  5. #5
    Registered User Codeplug's Avatar
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    Cat's code works as expected in VC 6.0 (it's not that bad).

    gg

  6. #6
    Skunkmeister Stoned_Coder's Avatar
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    I think from memory it was that bad and that one was fixed in a service pack. Have you got your v6c installation up to date magos?
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