fstream operator>> stops at white space

[khalid302]

I need to read a specific number of characters into an std::string
from a file regardless of the characters read.

* fstream operator>stops when it runs into a white space character.
* The global variant of fstream::getline works with std:string but
does not take a 'width' parameter.
* ifstream::get takes a 'width' parameter but does not work with
std::string.

I simply want to read a specific number of characters and only stop on
EOF. Is there any straight forward way to do it ?

[khalid302]

Resize the string first, and rely on the fact that in all (known) current

implementations it has contiguous buffer, and that will be guaranteed in C++0x.

I think std:string automatically accommodates input from operator>>.
am I missing something ?

Cheers, & hth.,

- Alf

[Ian Collins]

kh*******@gmail.com wrote:

>Resize the string first, and rely on the fact that in all (known) current
implementations it has contiguous buffer, and that will be guaranteed in C++0x.

I think std:string automatically accommodates input from operator>>.
am I missing something ?

I think Alf was telling you to do an unformatted read directly into the
string's buffer.

--
Ian Collins.

[khalid302]

On Aug 9, 1:44*am, Ian Collins <[e-mail]:

I think Alf was telling you to do an unformatted read directly into the
string's buffer.

What's the API for that, std::string has data() and c_str(), and both
return a const char* which can't/shouldn't be modified.

[khalid302]

The only solution I could think of, is to create a custom stream class
over cstdio ... C streams seem to be more mature.

[Ian Collins]

kh*******@gmail.com wrote:

On Aug 9, 1:44 am, Ian Collins <[e-mail]:

>I think Alf was telling you to do an unformatted read directly into the
string's buffer.

What's the API for that, std::string has data() and c_str(), and both
return a const char* which can't/shouldn't be modified.

&string[0]

--
Ian Collins.

[Juha Nieminen]

kh*******@gmail.com wrote:

The only solution I could think of, is to create a custom stream class
over cstdio ... C streams seem to be more mature.

std::string buffer(width, ' ');
inputFile.read(&buffer[0], width);

What's so hard about that?

[khalid302]

On Aug 9, 11:48*am, Juha Nieminen <[e-mail]:

* What's so hard about that?

Nothing, just never crossed my mind, thanks :)

[khalid302]

On Aug 9, 11:03*am, Ian Collins <[e-mail]:

&string[0]

Yeah, thanks.