[PATCH] m4/pthread-cond.m4: fix build without threads

[PATCH] m4/pthread-cond.m4: fix build without threads

[Fabrice Fontaine]

HAVE_PTHREAD_COND_xxx variables are wrongly set to 1 instead of 0 if
HAVE_PTHREAD_H is set to 0 since
https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=e08989ca11a13c8a09cb0c34f797af5a40753379

This will result in the following build failure if threads are not
available, for example with coreutils in version 8.32:

/home/buildroot/autobuild/run/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabihf/8.3.0/../../../../arm-buildroot-linux-uclibcgnueabihf/bin/ld: src/libsinglebin_sort.a(libsinglebin_sort_a-sort.o): in function `queue_insert':
sort.c:(.text+0x1d5c): undefined reference to `pthread_cond_signal'
/home/buildroot/autobuild/run/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabihf/8.3.0/../../../../arm-buildroot-linux-uclibcgnueabihf/bin/ld: src/libsinglebin_sort.a(libsinglebin_sort_a-sort.o): in function `sortlines':
sort.c:(.text+0x2868): undefined reference to `pthread_cond_wait'
/home/buildroot/autobuild/run/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabihf/8.3.0/../../../../arm-buildroot-linux-uclibcgnueabihf/bin/ld: src/libsinglebin_sort.a(libsinglebin_sort_a-sort.o): in function `single_binary_main_sort':
sort.c:(.text+0x5a24): undefined reference to `pthread_cond_init

Fixes:
 - http://autobuild.buildroot.org/results/acb58a76642c6ffd8f0b752349a6e754fc011e86

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
 m4/pthread-cond.m4 | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/m4/pthread-cond.m4 b/m4/pthread-cond.m4
index 75e37c613..f6ff6c0e6 100644
--- a/m4/pthread-cond.m4
+++ b/m4/pthread-cond.m4
@@ -23,14 +23,14 @@ AC_DEFUN([gl_PTHREAD_COND],
     REPLACE_PTHREAD_COND_DESTROY=1
   else
     if test $HAVE_PTHREAD_H = 0; then
-      HAVE_PTHREAD_COND_INIT=1
-      HAVE_PTHREAD_CONDATTR_INIT=1
-      HAVE_PTHREAD_CONDATTR_DESTROY=1
-      HAVE_PTHREAD_COND_WAIT=1
-      HAVE_PTHREAD_COND_TIMEDWAIT=1
-      HAVE_PTHREAD_COND_SIGNAL=1
-      HAVE_PTHREAD_COND_BROADCAST=1
-      HAVE_PTHREAD_COND_DESTROY=1
+      HAVE_PTHREAD_COND_INIT=0
+      HAVE_PTHREAD_CONDATTR_INIT=0
+      HAVE_PTHREAD_CONDATTR_DESTROY=0
+      HAVE_PTHREAD_COND_WAIT=0
+      HAVE_PTHREAD_COND_TIMEDWAIT=0
+      HAVE_PTHREAD_COND_SIGNAL=0
+      HAVE_PTHREAD_COND_BROADCAST=0
+      HAVE_PTHREAD_COND_DESTROY=0
     fi
   fi
 ])
-- 
2.30.2

Re: [PATCH] m4/pthread-cond.m4: fix build without threads

[Bruno Haible]

Hi,

Fabrice Fontaine wrote:
> HAVE_PTHREAD_COND_xxx variables are wrongly set to 1 instead of 0 if
> HAVE_PTHREAD_H is set to 0 since
> https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=e08989ca11a13c8a09cb0c34f797af5a40753379

Indeed, that's obviously a copy&paste mistake.

> This will result in the following build failure if threads are not
> available, for example with coreutils in version 8.32:

Thanks for the analysis and fix. Applied with a ChangeLog entry:


2021-04-04  Fabrice Fontaine  <fontaine.fabrice@gmail.com>

	pthread-cond: Fix wrong configure results when <pthread.h> is absent.
	* m4/pthread-cond.m4 (gl_PTHREAD_COND): When <pthread.h> does not exist,
	set HAVE_PTHREAD_COND_* to 0, not to 1.

diff --git a/m4/pthread-cond.m4 b/m4/pthread-cond.m4
index 75e37c6..8922a8a 100644
--- a/m4/pthread-cond.m4
+++ b/m4/pthread-cond.m4
@@ -1,4 +1,4 @@
-# pthread-cond.m4 serial 1
+# pthread-cond.m4 serial 2
 dnl Copyright (C) 2019-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -23,14 +23,14 @@ AC_DEFUN([gl_PTHREAD_COND],
     REPLACE_PTHREAD_COND_DESTROY=1
   else
     if test $HAVE_PTHREAD_H = 0; then
-      HAVE_PTHREAD_COND_INIT=1
-      HAVE_PTHREAD_CONDATTR_INIT=1
-      HAVE_PTHREAD_CONDATTR_DESTROY=1
-      HAVE_PTHREAD_COND_WAIT=1
-      HAVE_PTHREAD_COND_TIMEDWAIT=1
-      HAVE_PTHREAD_COND_SIGNAL=1
-      HAVE_PTHREAD_COND_BROADCAST=1
-      HAVE_PTHREAD_COND_DESTROY=1
+      HAVE_PTHREAD_COND_INIT=0
+      HAVE_PTHREAD_CONDATTR_INIT=0
+      HAVE_PTHREAD_CONDATTR_DESTROY=0
+      HAVE_PTHREAD_COND_WAIT=0
+      HAVE_PTHREAD_COND_TIMEDWAIT=0
+      HAVE_PTHREAD_COND_SIGNAL=0
+      HAVE_PTHREAD_COND_BROADCAST=0
+      HAVE_PTHREAD_COND_DESTROY=0
     fi
   fi
 ])