🚀 go-pugleaf

Markus Kuhn (mskuhn@unrza3.dialin.rrze.uni-erlangen.de) wrote:
: clive@stdc.demon.co.uk (Clive D.W. Feather) writes:

: >In article <4f67kg$11g@cortex.dialin.rrze.uni-erlangen.de>,
: >Markus Kuhn <mskuhn@cip.informatik.uni-erlangen.de> wrote:
: >> Why isn't there a standard way of allowing an ISO C program to switch
: >> the standard input and output into binary transparent mode (as with
: >> the "b" flag in fopen()/freopen() for normal files)?
: >>
: >> Has this just been forgotten or is there a good technical reason?

: >On some implementations, this decision has to be made at the time you
: >open the file and can't be changed.

: I would already be happy with a portable function that allows to
: switch stdin or stdout to binary mode and that has only a well-defined
: behaviour according to the standard if this switch occurs before any
: byte has been written to or read from the stream. This would cause no
: headaches on your computing fossil (because inserting a newline during
: a later switch would not be non-conforming) and would be sufficient
: for all important applications I can think of (like zcat).

You make an assumption that the operating system provides you with a means
of directing binary data into stdin or recieving it from stdout in the first
place. There is nothing to stop an operating system from insisting that 
stdin and stdout are conly onnected to a text terminal. If you are writing 
truely portable code then you would be better to not expect too much from
the OS.

[On the other hand I agree it would be useful to switch the mode though one
would have to accept it might fail or be useless - but almost anything to do 
with stdin and stdout can fail or be useless so that is not a bit deal. 
However there are plenty of other things to do with files that would be useful
such as switching from readonly to readwrite and truncating an already open 
file.]

--
Stephen Baynes                              baynes@mulsoc2.serigate.philips.nl
Philips Semiconductors Ltd
Southampton                                 My views are my own.
United Kingdom