RTEMS Targets Issue #2 - ftello()/fseeko()
Sun Mar 20 19:28:00 GMT 2016
On 2016-03-20 07:35, Corinna Vinschen wrote:
> On Mar 19 22:35, Yaakov Selkowitz wrote:
>> On 2016-03-19 12:10, Joel Sherrill wrote:
>>> But now have:
>>> #if __LARGEFILE_VISIBLE
>>> Does the newlib guard need tinkering, the RTEMS default
>>> features, or the test code in RTEMS?
>> feature_test_macros(7) says that _XOPEN_SOURCE >= 500 includes these two
>> largefile functions implicitly, but fseeko(3) says they are also
>> POSIX.1-2001. Does changing the guard to:
>> #if __LARGEFILE_VISIBLE || __POSIX_VISIBLE >= 200112
>> fix this issue?
> glibc's fseeko/ftello man page claims this guard:
> _FILE_OFFSET_BITS == 64 || _POSIX_C_SOURCE >= 200112L ||
> _XOPEN_SOURCE >= 600
> (defining the obsolete _LARGEFILE_SOURCE macro also works)
The joys of conflicting documentation. -D_XOPEN_SOURCE=600 will get you
_POSIX_C_SOURCE=200112L automatically, but -D_XOPEN_SOURCE=500 already
gets you __USE_LARGEFILE (as, per feature_test_macros(7),
_LARGEFILE_SOURCE is "implicitly defined if _XOPEN_SOURCE is defined
with a value greater than or equal to 500"), so 500 would be more
In any case, I'll post a patch for fseeko/ftello shortly.
> Note especially the _FILE_OFFSET_BITS == 64. So fseeko/ftello are
> always defined on systems with sizeof(off_t) == 8.
This is the exception to the "-D_FILE_OFFSET_BITS=64 as no affect on
64-bit systems" rule; try compiling with -ansi and you should see they
are not. Note that _POSIX_C_SOURCE=200809L is on by default, so maybe
that's what you're seeing?
More information about the Newlib