Re: Is use of 'binary' mode necessary to open files on NetBSD?

[John McCue <jmclists%jmcunx.com@localhost>]

On Sat, Dec 02, 2023 at 09:18:56AM +0530, Mayuresh wrote:
> I am using gcc 12.1 on NetBSD 9.3 amd64 in a c++ application that complies
> using standard std20.
>
> There is this c++ standard library class ifstream. Using method
> ifstream::open files are opened.
>
> So far I was under an impression that on BSDs / Linux / Unix like systems
> there is no need to explicitly pass the "b" option ( ifstream::binary in
> case of above API ) and that such option is required only on DOS / Windows
> systems.

Correct, it is due to how DOS Type Systems formats Text Files.

UNIX type systems use a \n at the end of the line.

DOS Type systems ends each line with a \r\n and upon read,
DOS type systems strips out the \r if 'b' is not supplied
when reading text files.

> But I found that without this option, on above setup, the things were not
> working (weird results you'd expect with implicit character conversions).
> Using above option solves the problem.
>
> On NetBSD, the fopen man page clearly says 'b' is ignored. So wonder if
> gcc layer introduces the need to use it in above usage pattern.
>
> A bit surprised by this behavior. Comments please.

I do not understand the behavior you are referring to.  I do
not know c++, but in c, 'b' is not needed on any UNIX type
system.  But for portability you can keep it for compile on
DOS Type systems.

I wonder if you are running into some specific c++ thing.

> --
> Mayuresh