Re: pg_preadv() and pg_pwritev()

Sergey Shinderuk <s.shinderuk@postgrespro.ru> writes:
> On 13.01.2021 12:56, Thomas Munro wrote:
>> On Wed, Jan 13, 2021 at 10:40 PM Sergey Shinderuk
>> <s.shinderuk@postgrespro.ru> wrote:
>>> note: 'pwritev' has been marked as being introduced in macOS 11.0 here,
>>> but the deployment target is macOS 10.15.0

>> Hrm...  So why did "configure" think you have pwritev, then?  It seems
>> like you must have been using different compilers or options at
>> configure time and compile time, no?

> No, i've just rerun configure from clean checkout without any options.
> It does think that pwritev is available. I'll try to figure this out
> later and come back to you. Thanks.

The symptoms sound consistent with using bleeding-edge Xcode on a
Catalina machine ... please report exact OS and Xcode versions.

I have a different complaint, using Big Sur and Xcode 12.3:

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file:
libpgport.a(pread.o)has no symbols 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file:
libpgport_shlib.a(pread_shlib.o)has no symbols 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file:
libpgport_srv.a(pread_srv.o)has no symbols 

Looks like we need to be more careful about not including pread.c
in the build unless it actually has code to contribute.

            regards, tom lane