diff mbox series

NEWS: Deprecate weak libpthread symbols for single-threaded checks

Message ID 875zad7yrc.fsf@oldenburg2.str.redhat.com
State Committed
Headers show
Series NEWS: Deprecate weak libpthread symbols for single-threaded checks | expand

Commit Message

Florian Weimer July 24, 2020, 2:50 p.m. UTC
Recommend the new __libc_single_thread variable instead.

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

Comments

Adhemerval Zanella July 24, 2020, 4:36 p.m. UTC | #1
On 24/07/2020 11:50, Florian Weimer via Libc-alpha wrote:
> Recommend the new __libc_single_thread variable instead.
> 
> ---
>  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
> 

Should we add it on the 'Major features' instead along with the single-threaded
entry?
Carlos O'Donell July 24, 2020, 8:40 p.m. UTC | #2
On 7/24/20 12:36 PM, Adhemerval Zanella via Libc-alpha wrote:
> 
> 
> On 24/07/2020 11:50, Florian Weimer via Libc-alpha wrote:
>> Recommend the new __libc_single_thread variable instead.
>>
>> ---
>>  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
>>
> 
> Should we add it on the 'Major features' instead along with the single-threaded
> entry?

No, it's good to call it out in the deprecated features. People might only
be looking at one or the other so we should have an entry in both.
Carlos O'Donell July 24, 2020, 8:40 p.m. UTC | #3
On 7/24/20 10:50 AM, Florian Weimer via Libc-alpha wrote:
> Recommend the new __libc_single_thread variable instead.
> 
> ---
>  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
> 

OK for 2.32.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
diff mbox series

Patch

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