p9p

System: Slackware Linux (version 14.2)
CPU: Intel(R) Core(TM) Duo CPU T2500 @2.00GHz
Deps: plan9port-20140306.tgz

https://code.google.com/archive/p/plan9port/downloads
plan9port-20140306.tgz

I recently compiled plan9port-20140306.tgz with Slackware-14.2's glibc-2.23.

The plan9port files' compilation produced terminal output as follows:

9c sam.c
/usr/include/features.h:148:3: warning: #warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE" [-Wcpp]
# warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE"

The suggestion has been forwarded to avoid the deprecated function usleep() in favour of
nanosleep(), the change of the feature test macro (FTM) appears to have occurred in glibc
subsequent to Slackware-14.1's glibc-2.17, so the warnings likely do not occur with those
releases.

The above file was uploaded March 2014.

9fans/plan9port/@657f699
include: define _DEFAULT_SOURCE
Since glibc 2.20, the _BSD_SOURCE and _SVID_SOURCE macros are
deprecated in favor of the _DEFAULT_SOURCE macro.

See https://sourceware.org/glibc/wiki/Release/2.20#Packaging_Changes
committed May 7, 2016

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I think it should be fine to replace usleep by nanosleep, but we have
to be sure it won't break compatibility with the various operating
systems people still run plan9port on.

--
D. du Colombier (djc)