On Thu, Jan 10, 2019 at 08:44:34AM -0800, Jay Foster wrote:
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.
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).
I filed this issue: https://github.com/alsa-project/alsa-utils/issues/9
Regards
Takashi Sakamoto