Hi,
I am relative new to C++ regarding it's functions and libraries. I need to
access files larger than 4GB which is AFAIK not possible with the STL
iostream - at least not if using a 32 bit compiler. iostream was my
favorite as my code has to work on files as well as memory buffers...
Could somebody please help me what functions/classes are the best in this
case?
BTW: I am currently using Visual C++ 2008 on Win32, but if possible I want
to write my code as "portable as possible".
Robert
19  7383 
Robert Kochem wrote:
I am relative new to C++ regarding it's functions and libraries. I need to
access files larger than 4GB which is AFAIK not possible with the STL
iostream - at least not if using a 32 bit compiler. iostream was my
favorite as my code has to work on files as well as memory buffers...
Have you actually tried and failed, or is that only your speculation?
Could somebody please help me what functions/classes are the best in this
case?
BTW: I am currently using Visual C++ 2008 on Win32, but if possible I want
to write my code as "portable as possible".
AFAIK, even standard C Library functions like fread and fseek should
work with large files. And since C++ I/O streams are relatively thin
wrappers around C streams, those are expected to work just as well.
Write a program, see if you get it to work, if not, post your code and
explain the situation.
V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask
Victor Bazarov schrieb:
Robert Kochem wrote:
>I am relative new to C++ regarding it's functions and libraries. I need to
access files larger than 4GB which is AFAIK not possible with the STL
iostream - at least not if using a 32 bit compiler. iostream was my
favorite as my code has to work on files as well as memory buffers...
Have you actually tried and failed, or is that only your speculation?
If you get a "possible loss of data" warning when feeding seekg() with an
64 bit integer - what would you expect?
AFAIK, even standard C Library functions like fread and fseek should
work with large files. And since C++ I/O streams are relatively thin
wrappers around C streams, those are expected to work just as well.
Write a program, see if you get it to work, if not, post your code and
explain the situation.
It may work for files, but can I work with them on memory streams?
Robert
Robert Kochem wrote:
Victor Bazarov schrieb:
>Robert Kochem wrote:
>>I am relative new to C++ regarding it's functions and libraries. I need to
access files larger than 4GB which is AFAIK not possible with the STL
iostream - at least not if using a 32 bit compiler. iostream was my
favorite as my code has to work on files as well as memory buffers...
Have you actually tried and failed, or is that only your speculation?
If you get a "possible loss of data" warning when feeding seekg() with an
64 bit integer - what would you expect?
I expect not to use seekg then. Or switch to a better implementation of
the library.
>
>AFAIK, even standard C Library functions like fread and fseek should
work with large files. And since C++ I/O streams are relatively thin
wrappers around C streams, those are expected to work just as well.
Write a program, see if you get it to work, if not, post your code and
explain the situation.
It may work for files, but can I work with them on memory streams?
I don't know what those are, sorry.
V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask
Hi,
Most 32 bit OS'es have a limitation of 2GB (maybe 4GB I am not sure about
that) per file. If the OS can handle both like for instance sun V440 or
ubuntu 64 or lots of others you can compile with m64 with gcc (and link to
64 versions of all libraries) and usually have the full 64 bit range.
Sometimes you have to add something like LARGE_FILE_SUPP ORT from the top of
my memory.
I havent' tried but maybe the same applies to 64 bit MS-Windows.
Regards, Ron AF Greve http://www.InformationSuperHighway.eu
"Robert Kochem" <ro****@mailueb erfall.dewrote in message
news:1b******** *************** *******@40tude. net...
Hi,
I am relative new to C++ regarding it's functions and libraries. I need to
access files larger than 4GB which is AFAIK not possible with the STL
iostream - at least not if using a 32 bit compiler. iostream was my
favorite as my code has to work on files as well as memory buffers...
Could somebody please help me what functions/classes are the best in this
case?
BTW: I am currently using Visual C++ 2008 on Win32, but if possible I want
to write my code as "portable as possible".
Robert
Victor Bazarov wrote:
>If you get a "possible loss of data" warning when feeding seekg() with an
64 bit integer - what would you expect?
I expect not to use seekg then. Or switch to a better implementation of
the library.
That is easy to say - but what else to use?
>It may work for files, but can I work with them on memory streams?
I don't know what those are, sorry.
May be that was not the correct name in the C++ realm: I need an
abstraction of the underlaying data source. My code have to work on files
as well as on memory buffers and I call a stream using a memory buffer as
source a memory stream.
Robert
Ron AF Greve schrieb:
Most 32 bit OS'es have a limitation of 2GB (maybe 4GB I am not sure about
that) per file.
Sorry, but I can't believe that. Do you really mean that e.g. a 32bit Linux
filesystem can not handle files larger than 4GB?
Robert
Hi,
In the past there certainly was a time it couldn't. Currently I haven't a
pure 32 bit linux version although I could test with 64 and compiling for 32
(maybe tomorrow) And I am sure a lot of OS'es indeed don't. Lookup your
flavor and search for large file support.
Regards, Ron AF Greve http://www.InformationSuperHighway.eu
"Robert Kochem" <ro****@mailueb erfall.dewrote in message
news:13******** *************** *****@40tude.ne t...
Ron AF Greve schrieb:
>Most 32 bit OS'es have a limitation of 2GB (maybe 4GB I am not sure about
that) per file.
Sorry, but I can't believe that. Do you really mean that e.g. a 32bit
Linux
filesystem can not handle files larger than 4GB?
Robert
Robert Kochem wrote:
Victor Bazarov wrote:
>>If you get a "possible loss of data" warning when feeding seekg() with an
64 bit integer - what would you expect?
I expect not to use seekg then. Or switch to a better implementation of
the library.
That is easy to say - but what else to use?
A different implementation. Check out 'STLport', Dinkumware...
>>It may work for files, but can I work with them on memory streams?
I don't know what those are, sorry.
May be that was not the correct name in the C++ realm: I need an
abstraction of the underlaying data source. My code have to work on files
as well as on memory buffers and I call a stream using a memory buffer as
source a memory stream.
So, are you going to write some kind of wrappers for C++ streams and
your own buffers, or are you going to provide your own streambuf
implementations that you're going to plug into C++ streams?
V
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