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fseek64()
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Hello there, do you have any idea where to get a good reference for the function fseek64?
Or does anyone of you here knows this function or is there really a fseek64 function? lol. Thanks!
Or does anyone of you here knows this function or is there really a fseek64 function? lol. Thanks!
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In addition, what function which is similar to stat that asks for a FILE* fildes rather than int fildes? Thanks!
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fseek64 isn't a standard function, so if it exists for your compiler, the documentation will tell you where to find it and how to use it. Have you tried fgetpos and fsetpos? They're designed for large files and the implementation typically uses a 64-bit type as the base for fpos_t.
>what function which is similar to stat that asks for a FILE* fildes rather than int fildes?
There isn't one. If you want that kind of functionality, you need to step outside the standard library.
>what function which is similar to stat that asks for a FILE* fildes rather than int fildes?
There isn't one. If you want that kind of functionality, you need to step outside the standard library.
Last edited by Narue; Oct 9th, 2007 at 9:18 am.
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I don't know anything about it, infact nothing about 64 bit programming. But a liitle google search helped me to find this.
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>> what function which is similar to stat that asks for a FILE* fildes rather than int fildes?
the function
this would give the file descriptor using which you can call fstat() which also conforms to posix.
the function
int fileno(FILE *stream); is part of both posix and single unix specifications. http://www.opengroup.org/onlinepubs/...ns/fileno.htmlthis would give the file descriptor using which you can call fstat() which also conforms to posix.
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@Narue - I have heared 'bout fsetpos but I did'nt know that it could deal with larger filetypes. I thought fsetpos64 is used. Thanks! I'll try this instead. Uhmm...have you ever encounter or use fseek64? Which is more preferable between fseek64 and fsetpos?
@vishesh - It says here that fseek64 and even fsetpos64 are new library interfaces? Do have any idea if gcc version 4.0+ supports these functions? Thanks, it really helped me, I'm keeping this document for future references.
@vijayan121 - This is exactly what I need. Thanks!
@all - Thank you very much.
@vishesh - It says here that fseek64 and even fsetpos64 are new library interfaces? Do have any idea if gcc version 4.0+ supports these functions? Thanks, it really helped me, I'm keeping this document for future references.
@vijayan121 - This is exactly what I need. Thanks!
@all - Thank you very much.
Last edited by jaepi; Oct 9th, 2007 at 10:34 pm.
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>I have heared 'bout fsetpos but I did'nt know that it could deal with larger filetypes.
That's what fsetpos and fgetpos are there for. fseek is limited to the size of a long integer, but because fsetpos and fgetpos rely on an opaque type (fpos_t) for representing the offset, implementations should be using a type that can handle the file size limit of the system. If your compiler doesn't do that, it's safe to assume that the rest of the standard library may be weak as well.
>Which is more preferable between fseek64 and fsetpos?
Between two functions that do the same thing, but with one being standard and the other not, choose the standard function. But make sure that they really do the same thing. If I were to implement fseek64 on my implementation it would look like this:
Which is identical to fseek because it uses fpos_t internally anyway. In other words, fseek64 would be a fluffy function for compatibility with existing code only. But I can't say how it's implemented on another implementation, so you'll have to do some research.
That's what fsetpos and fgetpos are there for. fseek is limited to the size of a long integer, but because fsetpos and fgetpos rely on an opaque type (fpos_t) for representing the offset, implementations should be using a type that can handle the file size limit of the system. If your compiler doesn't do that, it's safe to assume that the rest of the standard library may be weak as well.
>Which is more preferable between fseek64 and fsetpos?
Between two functions that do the same thing, but with one being standard and the other not, choose the standard function. But make sure that they really do the same thing. If I were to implement fseek64 on my implementation it would look like this:
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I'd rather use fsetpos. Uhmmm, btw, fgetpos and fsetpos come together, right? Or fsetpos may exist without fgetpos (vice-versa).
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Since this is a C question and not C++ I'm moving it over to the C board.
Don't PM me with questions -- you might get a nasty PM in response. If you have a question then post it in one of the forums.
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