Re: [Help-glpk] Parallel runs of glpk

[Mathieu Dutour]

Hi Andrew,

What about replacing

static void *tls = NULL;

by

thread_local void *tls = NULL;

The "thread_local" is certainly supported in C++ from C++11

and C11 has the _Thread_local.

(see http://en.cppreference.com/w/cpp/language/storage_duration)

and so it should be portable and address the issue cleanly.

Now, my second question would be for the "tls".

The variable "tls" is used by tls_set_ptr and tls_get_ptr which

are only used by glp_init_env, glp_free_env and get_env_ptr.

Proposed solution:

--- As of now the glp_init_env and glp_free_env are taking

a void. But we get very simply put a ENV *env as part of

their input. The "env" would then no longer be a global variable

but instead be a scope variable in the frame where the solver

is called.

--- several function glpapi06.c / glpapi08.c and glpapi09.c

are using get_env_ptr to get the pointer. Instead we could add

the env variable as part of their input.

I may be very naive but the only negative impact I see from

this solution is API breaks.

  Mathieu

On 14 December 2016 at 18:56, Andrew Makhorin <address@hidden> wrote:

On Wed, 2016-12-14 at 18:28 +0100, Mathieu Dutour wrote:
>         Please see
>         http://lists.gnu.org/archive/html/help-glpk/2010-04/msg00038.html .
>
>         If you are interested in this solution, I can post you a
>         reentrant
>         version of glpk/src/env/tls.c for GNU/Linux or MS Windows
>         (from an old
>         glpk distribution).
> Yes, thank you!
> I think this is the right solution.

For a GNU/Linux version see
http://lists.gnu.org/archive/html/help-glpk/2010-04/msg00043.html

Attached is a MS Windows dll version.

You need to replace glpk/src/env/tls.c and then rebuild the package as
usual.