Re: lock, tls, and single-threaded applications

[Jim Meyering]

Bruno Haible <address@hidden> wrote:
> Eric Blake wrote:
>> Next I'm wondering if we should add a module which invokes
>> gl_DISABLE_THREADS, as well as pulls in the unlocked-io module, for the
>> benefit of projects that are known to be single-threaded, as it is
>> slightly easier to add a module to the list of imports than it is to
>> modify configure.ac to manually invoke gl_DISABLE_THREADS.
>
> I don't think this would be a good idea, precisely because it is so easy,
> and because importing extra modules from gnulib otherwise is a no-brainer.
> But the decision whether to use gl_DISABLE_THREADS must be a conscious one.
> For example, if coreutils/src/sort.c becomes multithreaded, coreutils cannot
> use this macro.

Yep.  And it couldn't use the unlocked-io module, either.
That has made me consider (if/when sort does become
multithreaded) building specified multithreaded programs in
coreutils against a separate thread-safe gnulib instance,
so that the remaining 100 programs don't suffer just because
sort flipped the MT switch.