[mpich-devel] [mpich-commits] [mpich] MPICH primary repository branch, master, updated. v3.1.1-8-gbe93cae

[Dave Goodell (dgoodell)]

[accidentally responded to moderated commits@, not devel@]

On Jun 11, 2014, at 2:05 PM, Dave Goodell (dgoodell) <dgoodell at cisco.com> wrote:

> On Jun 11, 2014, at 11:01 AM, Service Account <noreply at mpich.org> wrote:
> 
>> commit be93caec6c6b9b230fbde9b1b296cde001fde934
>> Author: Antonio J. Pena <apenya at mcs.anl.gov>
>> Date:   Mon Jun 9 17:12:17 2014 -0500
>> 
>>   Added support for thread-safe errno in Solaris
>> 
>>   The _REENTRANT macro is required to be defined in order to get
>>   thread-safe "errno" values. Modern POSIX systems provide this by default
>>   when using -lpthreads, but there are still some (Solaris) that require
>>   an explicit define. Since we weren't compiling with that macro, we were
>>   getting incorrect "errno" values from the threads (mainly 0).
>> 
>>   More details: since we use nonblocking sockets, our code was checking
>>   "errno" to not be EINPROGRESS whenever we got an error code from a
>>   connect/accept, in order to determine an actual error (a return value
>>   of -1 and errno of EINPROGRESS does not define an actual error but a
>>   "not yet" when using nonblocking sockets).
> 
> Interesting, I did not know about this Solaris "quirk".
> 
>>   This patch automatically gets this macro defined by configure whenever
>>   we are not building in MPI_THREAD_SINGLE mode only.
>> 
>>   Fixes #2107
>> 
>>   Signed-off-by: Ken Raffenetti <raffenet at mcs.anl.gov>
>> 
>> diff --git a/configure.ac b/configure.ac
>> index 936f6ce..96545b0 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -1352,6 +1352,13 @@ fi
>> export MPICH_THREAD_LEVEL
>> AC_DEFINE_UNQUOTED(MPICH_THREAD_LEVEL,$MPICH_THREAD_LEVEL,[Level of thread support selected at compile time])
>> 
>> +# If not in MPI_THREAD_SINGLE, we need -D_REENTRANT to get thread-safe "errno".
>> +# Most POSIX systems provide this by default when using -lpthread, but we only use it in MPI_THREAD_MULTIPLE.
>> +# Some systems (Solaris) still require an explicit define in any case.
>> +if test "$MPICH_THREAD_LEVEL" != "MPI_THREAD_SINGLE"; then
>> +    PAC_APPEND_FLAG([-D_REENTRANT], [CFLAGS])
> 
> A largely academic observation, but: should this be CPPFLAGS instead?
> 
> -Dave
>