sendfile_posix: only use *64 APIs when _LARGEFILE64_SOURCE is defined

[aberaud]

64 APIS are considered deprecated and should not be used unless _LARGEFILE64_SOURCE is explicitly defined.

[eao197]

Hi!

64 APIS are considered deprecated

Could you please provide a reference to a document that declares the Large-File Summit (LFS) specification for POSIX deprecated?

[aberaud]

Hi,

The API with 64 suffix is called the transitional LFS API and is mostly designed to be used by legacy 32 bits systems.

As documented by glibc for _LARGEFILE64_SOURCE:

This macro was introduced as part of the Large File Support extension (LFS). It is a transition interface for the period when 64 bit offsets are not generally used (see _FILE_OFFSET_BITS).

The modern way to manage large files is to use the standard POSIX API (without 64) with _FILE_OFFSET_BITS=64.

In any case, APIs with 64 at the end must not be used if _LARGEFILE64_SOURCE is not defined, so this patch fixes that.

[eao197]

Hi, @aberaud !

Thanks you very much for the explanation.

We'll take a closer look at it the next week.