[glibc] NEWS: Deprecate weak libpthread symbols for single-threaded checks

[glibc] NEWS: Deprecate weak libpthread symbols for single-threaded checks

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=89c255294a5b14dd88e45ed3b2a2a66517ed1a6f

commit 89c255294a5b14dd88e45ed3b2a2a66517ed1a6f
Author: Florian Weimer <fweimer@redhat.com>
Date:   Fri Jul 24 16:50:38 2020 +0200

    NEWS: Deprecate weak libpthread symbols for single-threaded checks
    
    Recommend the new __libc_single_thread variable instead.
    
    Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Diff:
---
 NEWS | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/NEWS b/NEWS
index 83aed60e19..7fb167e650 100644
--- a/NEWS
+++ b/NEWS
@@ -134,6 +134,14 @@ Deprecated and removed features, and other changes affecting compatibility:
   or contents might be overwritten on subsequent calls in the same thread or
   if the thread is terminated.  It makes strerror MT-safe.
 
+* Using weak references to libpthread functions such as pthread_create
+  or pthread_key_create to detect the singled-threaded nature of a
+  program is an obsolescent feature.  Future versions of glibc will
+  define pthread_create within libc.so.6 itself, so such checks will
+  always flag the program as multi-threaded.  Applications should check
+  the __libc_single_threaded variable declared in
+  <sys/single_threaded.h> instead.
+
 * The "files" NSS module no longer supports the "key" database (used for
   secure RPC).  The contents of the /etc/publickey file will be ignored,
   regardless of the settings in /etc/nsswitch.conf.  (This method of