> As far as I can make out from the libc docs, largefile support is
> automatic if the macro _GNU_SOURCE is defined and the kernel supports
> large files.
>
> Is that a correct understanding? or do I actually need to do something
> special to ensure that pg_dump supports large files?
in this case you still have to use large file functions in the code
explicitly
the easiest way to get large file support is to pass
-D_FILE_OFFSET_BITS=64 to the preprocessor, and I think I remember doing
this once for pg_dump
see /usr/include/features.h
Best regards
Helge