Re: [BUG] Unix Builds Requires Pthread Support (was [PATCH v4 00/12] Simple IPC Mechanism)

[Jeff King <peff@peff.net>]

On Tue, May 18, 2021 at 09:37:38AM -0400, Randall S. Becker wrote:

> >+# All simple-ipc requires threads, and then individual # mechanisms
> >+have their own requirements.
> >+ifndef NO_PTHREADS
> >+	BASIC_CFLAGS += -DSUPPORTS_SIMPLE_IPC
> > 	LIB_OBJS += compat/simple-ipc/ipc-shared.o
> >+ifndef NO_UNIX_SOCKETS
> > 	LIB_OBJS += compat/simple-ipc/ipc-unix-socket.o
> > endif
> >-
> > ifdef USE_WIN32_IPC
> >-	LIB_OBJS += compat/simple-ipc/ipc-shared.o
> > 	LIB_OBJS += compat/simple-ipc/ipc-win32.o  endif
> >+endif
> >
> > ifdef NO_ICONV
> > 	BASIC_CFLAGS += -DNO_ICONV
> >diff --git a/simple-ipc.h b/simple-ipc.h index dc3606e30b..0f58be7945 100644
> >--- a/simple-ipc.h
> >+++ b/simple-ipc.h
> >@@ -4,11 +4,6 @@
> > /*
> >  * See Documentation/technical/api-simple-ipc.txt
> >  */
> >-
> >-#if defined(GIT_WINDOWS_NATIVE) || !defined(NO_UNIX_SOCKETS) -#define SUPPORTS_SIMPLE_IPC -#endif
> >-
> > #ifdef SUPPORTS_SIMPLE_IPC
> > #include "pkt-line.h"
> 
> I'm not sure this is going to work. The platform *does* support UNIX
> sockets (and not disabled) and pthreads, but we have disabled pthreads
> in our build. So in the above, ipc-unix-socket.o will be included at
> the ifndef NO_UNIX_SOCKETS. If NO_PTHREADS, not being pedantic, there
> should be no pthread references, regardless of other considerations.
> Although, at some point, I hope to resolve why pthreads (PUT) is
> having issues in git on the platform but not at this point.

Unless I screwed something up, it shouldn't be. There's an outer ifndef
for NO_PTHREADS. Double negation aside, that means that we don't even
hit the ifndef NO_UNIX_SOCKETS inside it unless we now pthreads are
supported. And so we do not include ipc-unix-socket.o.

For the SUPPORTS_SIMPLE_IPC flag, I just moved the logic into the
Makefile. It could continue to live in simple-ipc.h, too (but then that
is basically a repetition of the Makefile logic; it would have to learn
the same "only if pthreads are available" conditional, too).

-Peff