[Libburn-hackers] Re: Issue burning CD-RW with unpredictable data size

Thomas Schmitt scdbackup at gmx.net
Tue Apr 6 02:19:31 CDT 2010


Hi,

it turned out that Joris' problem with the test
version of libburner was due to 32-bit off_t in
the application whereas libburn prescribes 64-bit
off_t.
The app sent down 32 bit and libburn took 64.
This caused random size evaluation of the
input pipe rather than size 0, which would have
indicated unpredictable size. This led to write
mode SAO rather than TAO.

The test program runs as expected if it gets
these two macro definitions which affect the
compiler:
    #define _LARGEFILE_SOURCE
    #define _FILE_OFFSET_BITS 64

Joris is now exploring whether this helps his
own applicationi, too.

------------------------------------------------

I am pondering how i can force 64-bit off_t
onto applications on 32-bit machines.

The problem is that this is in the realm of
configuration and not of source code. It depends
on the operating system resp. compiler.

Further, the off_t size must not be mixed in the
application. If i put these macros into
libburn.h, then it would possibly influence only
a few source modules of an application, whereas
others continue to compile off_t to 32 bit.

Does anybody know how other libraries ideal with
this problem ?


Have a nice day :)

Thomas



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