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Ron Natalie
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 Posted: Fri Aug 15, 2003 9:25 pm Post subject: Re: std::ends useful? |
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"Saul" <stamari (AT) bigfoot (DOT) com> wrote
| Quote: | Is std::ends useful in any way (not considering strstream) ?
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Well, if you need a way to put a null into a stream it is. Of course, outside
of strsteram, there's no overriding need to put a null into stream (and you
could
always output a ' ', ends doesn't even do a flush like endl does).
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Maciej Sobczak
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| Posted: Mon Aug 18, 2003 10:37 am Post subject: Re: std::ends useful? |
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Hi,
Saul wrote:
| Quote: | Is std::ends useful in any way (not considering strstream) ?
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It all depends on what you expect on the other "side" of the stream.
Let's suppose that the stream is wrapped around a network socket and
that the application on the other side (here, on the other side of the
wire) expects that every string is zero-terminated. This is reasonable
and I bet that there are many servers working this way.
std::ends can be useful to explicitly inject zeros into the stream.
Of course, you can also do this by:
s << ' ';
--
Maciej Sobczak
http://www.maciejsobczak.com/
Distributed programming lib for C, C++, Python & Tcl:
http://www.maciejsobczak.com/prog/yami/
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Daniel Spangenberg
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| Posted: Mon Aug 18, 2003 4:37 pm Post subject: Re: std::ends useful? |
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Maciej Sobczak schrieb:
[snip9
| Quote: | std::ends can be useful to explicitly inject zeros into the stream.
Of course, you can also do this by:
s << ' ';
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One advantage of ends versus ' ' is the fact, that you can use ends
more easily in generic code, which doesn't know its character type.
(Otherwise you have to define a typedef for the character type and
could use char_type() instead).
Yours,
Daniel
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Francis Glassborow
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| Posted: Mon Aug 18, 2003 11:49 pm Post subject: Re: std::ends useful? |
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In article <bhoea4$s4f$1 (AT) nemesis (DOT) news.tpi.pl>, Maciej Sobczak
<maciej (AT) maciejsobczak (DOT) com> writes
| Quote: | Hi,
Saul wrote:
Is std::ends useful in any way (not considering strstream) ?
It all depends on what you expect on the other "side" of the stream.
Let's suppose that the stream is wrapped around a network socket and
that the application on the other side (here, on the other side of the
wire) expects that every string is zero-terminated. This is reasonable
and I bet that there are many servers working this way.
std::ends can be useful to explicitly inject zeros into the stream.
Of course, you can also do this by:
s << ' ';
|
but ends avoids the use of a magic number. However I wish it had been
differently named such as end_str.
--
Francis Glassborow ACCU
64 Southfield Rd
Oxford OX4 1PA +44(0)1865 246490
All opinions are mine and do not represent those of any organisation
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Ron Natalie
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| Posted: Tue Aug 19, 2003 11:28 pm Post subject: Re: std::ends useful? |
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"Francis Glassborow" <francis (AT) robinton (DOT) demon.co.uk> wrote in message
| Quote: |
std::ends can be useful to explicitly inject zeros into the stream.
Of course, you can also do this by:
s << ' ';
but ends avoids the use of a magic number. However I wish it had been
differently named such as end_str.
|
There's no "magic number." A null character is always , it's no more
magic than n is a newline.
The only real compelling argument I've heard is that ends works independent
of the char type of the streams. Otherwise you potentially need to use
L' ' or some other value.
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Maciej Sobczak
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| Posted: Wed Aug 20, 2003 1:59 pm Post subject: Re: std::ends useful? |
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Hi,
Ron Natalie wrote:
| Quote: | The only real compelling argument I've heard is that ends works independent
of the char type of the streams. Otherwise you potentially need to use
L' ' or some other value.
|
The argument behind ends being independent is much more compelling. 
It is not only independent, it is *generic*.
Consider:
template <class Stream>
void endAndFlush(Stream &s)
{
s << ends << flush;
}
This code works with all kinds of streams and is suitable for any
stream-like being without changes. When you use (more or less) magic
numbers like ' ' or L' ' (or some other value), you always bind your
code to the particular type of character used in the stream. With ends
the code is not bound to anything and the compiler will happily resolve
it to what is actually appropriate.
In this context, ' ', L' ', 'n', L'n', etc. *are* magic, because
they have fixed target "platform" (the type of stream).
In contrast, the manipulators ends, endl, flush, etc. are not magic,
because they are not bound to any particular type of stream.
--
Maciej Sobczak
http://www.maciejsobczak.com/
Distributed programming lib for C, C++, Python & Tcl:
http://www.maciejsobczak.com/prog/yami/
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
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Bo Persson
Guest
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| Posted: Thu Aug 21, 2003 10:52 am Post subject: Re: std::ends useful? |
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"Ron Natalie" <ron (AT) sensor (DOT) com> skrev i meddelandet
news:3f423226$0$153$9a6e19ea (AT) news (DOT) newshosting.com...
| Quote: |
"Francis Glassborow" <francis (AT) robinton (DOT) demon.co.uk> wrote in message
std::ends can be useful to explicitly inject zeros into the
stream.
Of course, you can also do this by:
s << ' ';
but ends avoids the use of a magic number. However I wish it had
been
differently named such as end_str.
There's no "magic number." A null character is always , it's no
more
magic than n is a newline.
The only real compelling argument I've heard is that ends works
independent
of the char type of the streams. Otherwise you potentially need to
use
L' ' or some other value.
|
Maybe not. All streams inheriting from std::basic_ostream would have
this inserter
template
basic_ostream<_CharT, _TraitsT>&
operator<<(basic_ostream<_CharT, _TraitsT>& _Stream, char
_Char);
which will supposedly widen the char as needed.
Bo Persson
[email]bop2 (AT) telia (DOT) com[/email]
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
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