On Tue, Apr 25, 2006 at 09:34:16 +0800, Derry Wang wrote: > no matter how many bits are the offset type defined, you still can > access file again and again. > llseek will put file pointer in the offset position. Then you can call > llseek again and again. > Till the file pointer is in the position what you want. Totally useless, really. 2^32 is 2GB. Imagine you have 200GB file -- so you would call llseek 50 times to get in the middle! Besides the 32-bit interface will probably refuse to work with large files anyway. There is actually a macro, that has to be defined before importing features.h that affects how off_t gets defined (and therefore which interface will be provided by libc) - _LARGEFILE_SOURCE and _LARGEFILE64_SOURCE. > derry > > pradeep singh wrote: > > >Hi all > >llseek method has its second argument as offset which is of type unsigned > >long. > >And the last argument decides whence i.e from where to start the offset, > >right? > >Now i have a doubt. > >If the data type of offset is unsigned long this means i can only > >access a file till its 2^32 byte after if i start from its beginning, > >using llseek. > >On the other hand ulimit -a shows me i can have a file size of > >unlimited size, which is indeed some value subjected to storage space > >on which file resides and also the filesystem.right? > > > >Then does this means i cant access a file beyond its 2^32 byte using > >llseek and starting from its beginning? > > > >Is it so or am i missing something here? > >Any pointers or links will be appreciated. > >Thank you. > >Pradeep > >-- > >play the game > > > >-- > >Kernelnewbies: Help each other learn about the Linux kernel. > >Archive: http://mail.nl.linux.org/kernelnewbies/ > >FAQ: http://kernelnewbies.org/faq/ > > > > > > > > > > > > > > -- > Kernelnewbies: Help each other learn about the Linux kernel. > Archive: http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > -- Jan 'Bulb' Hudec <bulb@xxxxxx>
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