On 1/10/2019 12:31 AM, Jaroslav Kysela wrote:
Dne 10.1.2019 v 05:24 Takashi Sakamoto napsal(a):
Hi,
I'm an author of axfer.
On Tue, 08 Jan 2019 18:00:18 +0100, Jay Foster wrote:
I am attempting to build the 1.1.8 release of alsa-utils and getting
an error about POLLRDNORM (and others) undefined. This error comes
from axfer/waiter-select.c. axfer/waiter-select.c includes
"waiter.h", which includes "poll.h". This build is for a linux
target.
On Wed, 09 Jan 2019 17:22:36 +0100, Jay Foster wrote:
On 1/9/2019 3:10 AM, Takashi Iwai wrote:
Which libc are you using? The POSIX man page (man poll.h) mentions
POLLRDNORM defined there, at least, on my system with glibc 2.27.
This is a legacy ARM product using glibc 2.9.
I'm sorry for the FTBFS but it's out of my notice to build with too-old glibc.
Here, a history of glibc for related events:
* glibc-2.9: 2008/11/13
* your version
* glibc-2.10: 2009/5/9
* support XPG7/POSIX-2008
* add '__USE_XOPEN2k8' for the avove
* glibc-2.19: 2014/2/7
* add '_DEFAULT_SOURCE' macro
* XPG7/POSIX-2008 is a default behaviour
* glibc-2.20: 2014/9/7
* obsolete '_BSD_SOURCE' and '_SYSV_SOURCE' macros
* glibc-2.28: 2018/8/1
* used my environment (Ubuntu 18.10)
The macros, POLLRDNORM and the others, seems to be defined officially in
POSIX-2008 and nowadays glibc supports POSIX-2008 as a default. This is
the reason that I've never faced your issue in my development period.
I guess it's the reason that nothing noted in man of poll(2) and
select(2).
I need a bit time to judge whether it's woth to support such old-glibc.
Just removal of the newly-introduced macros is a simple solution.
We may add those definitions to CFLAGS (-D) through configure for the
old libs. Or just used #ifdef in the waiter-select.c - it's only one
place which uses this at this moment, but it's only quick workaround.
Jaroslav
I can resolve the issue by adding -D_GNU_SOURCE to my CFLAGS when
building alsa-utils. It would also be acceptable (to me) if you did
nothing about this.
If you wish to check the version of glibc for support of POLLRDNORM
through configure and add -D_GNU_SOURCE for older versions, that may
work too. I can report that-D_GNU_SOURCE is not needed with glibc
2.22. I am not sure precisely which version the POLLRDNORM (and
friends) were enabled by default. I can imagine a configure test that
compiled a test app which tries to use POLLRDNORM, and if it compiles
successfully, then nothing else is needed. If not, try again with
-D_GNU_SOURCE, and if that works, add -D_GNU_SOURCE to the CFLAGS. Such
a test might also be conditional on selecting waiter-select (the only
place this is used).
Jay
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