Beman Dawes wrote:
>
>
> >a) Why does basic_string::copy() not also copy an ending '\0'? If
> >there's some sort of good reason, why wasn't a function added that did
> >this (perhaps basic_string::copy_null() or something)? I must say, it
> >is very inconvenient to copy a string to a C-style array of chars with
> >the current string class.
>
> There is such a function - it is called c_str().

well, to be equivilent, it would really be:

strncpy ( buffer, string::c_str(), x );
buffer[x] = 0; // only if strlen(buffer > x), but it's not safe
  // to check that way, since strlening a non-termed
  // char[] is a bad thing
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I'm probably beating a dead horse here, but I had a couple of
questions about the strings class (at least, the one in the April WP).
Specifically, there are two design decisions that I don't understand.

a) Why does basic_string::copy() not also copy an ending '\0'? If
there's some sort of good reason, why wasn't a function added that did
this (perhaps basic_string::copy_null() or something)? I must say, it
is very inconvenient to copy a string to a C-style array of chars with
the current string class.

b) I don't see any reason why basic_string::copy() is not a const
function. Any particular reason for that one?



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In article <3150756f.168603020@sqarc.sq.com> willer@carolian.com (Steve
Willer) writes:

|> I'm probably beating a dead horse here, but I had a couple of
|> questions about the strings class (at least, the one in the April WP).
|> Specifically, there are two design decisions that I don't understand.

|> a) Why does basic_string::copy() not also copy an ending '\0'? If
|> there's some sort of good reason, why wasn't a function added that did
|> this (perhaps basic_string::copy_null() or something)? I must say, it
|> is very inconvenient to copy a string to a C-style array of chars with
|> the current string class.

Perhaps because it is so easy to write:

 dst[ s.copy( dst , sizeof( dst ) - 1 ) ] = '\0' ;

I'll admit that I don't particularly care for this style: too many side
effects in the indexing expression for readability.  But it does fit in
with the C/C++ tradition.

|> b) I don't see any reason why basic_string::copy() is not a const
|> function. Any particular reason for that one?

In my copy of the draft, it is const.
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GABI Software, Sarl., 8 rue des Francs Bourgeois, 67000 Strasbourg, France
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>I'm probably beating a dead horse here, but I had a couple of
>questions about the strings class (at least, the one in the April WP).
>Specifically, there are two design decisions that I don't understand.
>
>a) Why does basic_string::copy() not also copy an ending '\0'? If
>there's some sort of good reason, why wasn't a function added that did
>this (perhaps basic_string::copy_null() or something)? I must say, it
>is very inconvenient to copy a string to a C-style array of chars with
>the current string class.

There is such a function - it is called c_str().

>b) I don't see any reason why basic_string::copy() is not a const
>function. Any particular reason for that one?

copy() is const in the current WP.


--Beman Dawes
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