Builder C++ large files support for simple C program

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11-21-2007
Murfury

Builder C++ large files support for simple C program

I had to write a C program and ran it on Solaris server(only command line access). It seemed to me that it was easier to debug program on my notebook under Windows and then with minor modifications copy it to the server and ran.
I wrote a program at C++Builder 6.

Hovewer, there some inconsistencies between Borland and Unix <sys/stat.h> library. CC in Solaris offers functions like stat64, fseeko64 etc which designed to work with large files > 2Gb... but in Builder I can find only standard stat, fseek, etc,

At first, I debugged program on my Windows PC with small files. Hovewer, now I when I run the program on the server, sometimes I get "Core dump" error especially for very large files. It seems a kind of overflow. But I can't test program in a good debugger in Windows because of Builder <sys/stat.h> problem.

Pleese, give me advise, what is the easiest way to solve this
11-22-2007
dwks

C99 has fsetpos() and fgetpos(), which were introduced to solve this exact problem. The offsets that they use are 64-bit integers, I believe. However, I'm not sure if Borland C++ would support them. You might have to use compiler-specific functions.
11-22-2007
Murfury

Quote:

Originally Posted by dwks

C99 has fsetpos() and fgetpos(), which were introduced to solve this exact problem. The offsets that they use are 64-bit integers, I believe.

Sorry, in all compilers I saw...f_post from fgetpos is long not 64-bit integer....As I mentioned above ... I just looking for a Windows compiler with good debugger which has functions like fsetpos64() in stdio.h

I found _stati64() but I can't find Builder peers for Unix fgetpos64(), and fseeko64() functions
11-23-2007
dwks

[edit]

Quote:

Sorry, in all compilers I saw...f_post from fgetpos is long not 64-bit integer....As I mentioned above ... I just looking for a Windows compiler with good debugger which has functions like fsetpos64() in stdio.h

Did you try GCC via Code::Blocks? [/edit]

On the one hand, fgetpos() and fsetpos() definitely have a greater range than fseek() and ftell(): http://publications.gbdirect.co.uk/c...access_io.html:

Quote:

Note that for ftell and fseek it must be possible to encode the value of the file position indicator into a long. This may not work for very long files, so the Standard introduces fgetpos and fsetpos which have been specified in a way that removes the problem.

Perhaps f[gs]etpos() use unsigned variables at least, which would allow 4 GB files. (Several older file systems limit you to this size anyway.)

On the other hand, it does seem that f[gs]etpos64() have a greater range than ordinary f[gs]etpos(): http://www.mkssoftware.com/docs/man3/fgetpos.3.asp

It seems that f[gs]etpos64() are part of this library, perhaps you can get it for your intended platforms. http://www.mkssoftware.com/docs/man5/lf64.5.asp
This also looks like it might have some useful information: http://www.mkssoftware.com/docs/man5/lfcompile.5.asp

Nowhere is the actual range of f[gs]etpos() mentioned, although I imagine it must be at least 4GB, because it's supposed to be greater range than fseek()/ftell(), which support 2GB (they use longs).