Large files

Raimo Niskanen <>
Mon Dec 12 16:31:12 CET 2005

This feature was actually on its way into R10B-9, but in the last
minute it turned out that it broke the possibility of using 
cpu_timestamp on call traces, so we are working on an improved

 (Miguel Barreiro) writes:

> Hi,
> Support for large files (large being >= 2GB which is actually "moderately sized
> files" these days) works ok on 64-bit systems. Doesn't anyone else use large
> files on 32-bit systems? In case people is interested it works with the
> following recipe:
> - Either patch the file driver to open files with O_LARGEFILE and change a
> couple variables from off_t to off64_t and make sure they are correctly packed
> into 64-bit commands and responses or, much simpler:
> $ export CFLAGS="-D_FILE_OFFSET_BITS=64" ; ./configure ; make
> (remember to use clean sources). See the libc documentation for details on the
> - Apply the attached patch to make file:position/2 work correctly (everything
> else works without the patch, AFAIK). Currently
> erts/emulator/drivers/common/efile_drv.c packs the return value of lseek(2)
> using reply_Uint (which BTW is a bit misleading -- Uint is typedef'ed to a
> pointer-sized variable and not an unsigned int as I would tend to expect. These
> don't always match). The return value of lseek is off_t which may not be Uint
> sized, so I added a reply_off_t function.
> Patch generated against R108-B.
> Regards,
> Miguel


/ Raimo Niskanen, Erlang/OTP, Ericsson AB

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