Re: [Xenomai-core] [PATCH] posix: Avoid double declarations

[Jan Kiszka <jan.kiszka@domain.hid>]

Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> Gilles Chanteperdrix wrote:
>>> Jan Kiszka wrote:
>>>> Gilles Chanteperdrix wrote:
>>>>> Jan Kiszka wrote:
>>>>>> Please pull from git://git.xenomai.org/xenomai-jki.git for-upstream
>>>>>> and run bootstrap.
>>>>>>
>>>>>> ---------->
>>>>>>
>>>>>> Recent glibc versions come with support for
>>>>>> pthread_mutexattr_get/setprotocol and pthread_condattr_get/setclock.
>>>>>> Make sure we don't declare those prototypes in Xenomai's pthread.h a
>>>>>> second time as this can cause g++ warnings and even errors.
>>>>>>
>>>>>> Signed-off-by: Jan Kiszka <jan.kiszka@domain.hid>
>>>>>> ---
>>>>>>
>>>>>>  configure.in            |    4 ++--
>>>>>>  include/posix/pthread.h |    4 ++++
>>>>>>  2 files changed, 6 insertions(+), 2 deletions(-)
>>>>>>
>>>>>> diff --git a/configure.in b/configure.in
>>>>>> index b291ce4..6a8b821 100644
>>>>>> --- a/configure.in
>>>>>> +++ b/configure.in
>>>>>> @@ -750,8 +750,8 @@ if test x$CONFIG_XENO_POSIX_UITRON_MLOCKALL = xy; then
>>>>>>  fi
>>>>>>  
>>>>>>  save_LIBS="$LIBS"
>>>>>> -LIBS="$LIBS -lrt"
>>>>>> -AC_CHECK_FUNCS([shm_open shm_unlink mmap64 ftruncate64])
>>>>>> +LIBS="$LIBS -lrt -lpthread"
>>>>>> +AC_CHECK_FUNCS([shm_open shm_unlink mmap64 ftruncate64 pthread_mutexattr_setprotocol pthread_condattr_setclock])
>>>>>>  LIBS="$save_LIBS"
>>>>>>  
>>>>>>  AC_MSG_CHECKING(whether to enable dlopen support for skin libraries)
>>>>>> diff --git a/include/posix/pthread.h b/include/posix/pthread.h
>>>>>> index 2344158..98db325 100644
>>>>>> --- a/include/posix/pthread.h
>>>>>> +++ b/include/posix/pthread.h
>>>>>> @@ -418,17 +418,21 @@ int pthread_intr_control_np(pthread_intr_t intr,
>>>>>>  extern "C" {
>>>>>>  #endif
>>>>>>  
>>>>>> +#ifndef HAVE_PTHREAD_MUTEXATTR_SETPROTOCOL
>>>>>>  int pthread_mutexattr_getprotocol(const pthread_mutexattr_t *attr,
>>>>>>  				  int *proto);
>>>>>>  
>>>>>>  int pthread_mutexattr_setprotocol(pthread_mutexattr_t *attr,
>>>>>>  				  int proto);
>>>>>> +#endif
>>>>> That is not enough, if these functions are defined, then the
>>>>> PTHREAD_PRIO_NONE, PTHREAD_PRIO_INHERIT, PTHREAD_PRIO_PROTECT are going
>>>>> to be defined.
>>>>>
>>>>> Are you sure that the missing "restrict" are not causing the errors ?
>>>> This is enough to fix our build breakage due to different prototypes of
>>>> those functions, at least under C++. The magic __THROW may make the
>>>> difference, but I didn't test that in details as I think its simply
>>>> fragile to redeclare them.
>>>>
>>>> Don't know if those constants can cause trouble, they didn't do so here
>>>> so far. But I can Include them if preferred.
>>> If it works, it is just as fragile as trying to match function
>>> declarations of Xenomai's pthread.h and glibc's pthread.h.
>> Nope, because you don't repeat function attributes for their
>> definitions. So Xenomai's pthread lib should pick up what the host
>> header declares.
> 
> Currently, PTHREAD_PRIO_NONE, PTHREAD_PRIO_INHERIT and
> PTHREAD_PRIO_PROTECT are defined in Xenomai's header unconditionnaly.
> You see no warning or error because they are defined in an enum in
> glibc. But this is a fragile situation.
> 

I could offer this version and later add a patch to provide the missing
__real prototypes for all POSIX wrappers.

Jan

-------->

Recent glibc versions come with support for
pthread_mutexattr_get/setprotocol and pthread_condattr_get/setclock.
Make sure we don't declare those prototypes in Xenomai's pthread.h a
second time as this can cause g++ warnings and even errors. Also
exclude mutexattr related constants at this chance.

Signed-off-by: Jan Kiszka <jan.kiszka@domain.hid>
---

 configure.in            |    4 ++--
 include/posix/pthread.h |    7 +++++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/configure.in b/configure.in
index b291ce4..6a8b821 100644
--- a/configure.in
+++ b/configure.in
@@ -750,8 +750,8 @@ if test x$CONFIG_XENO_POSIX_UITRON_MLOCKALL = xy; then
 fi
 
 save_LIBS="$LIBS"
-LIBS="$LIBS -lrt"
-AC_CHECK_FUNCS([shm_open shm_unlink mmap64 ftruncate64])
+LIBS="$LIBS -lrt -lpthread"
+AC_CHECK_FUNCS([shm_open shm_unlink mmap64 ftruncate64 pthread_mutexattr_setprotocol pthread_condattr_setclock])
 LIBS="$save_LIBS"
 
 AC_MSG_CHECKING(whether to enable dlopen support for skin libraries)
diff --git a/include/posix/pthread.h b/include/posix/pthread.h
index 2344158..10176ad 100644
--- a/include/posix/pthread.h
+++ b/include/posix/pthread.h
@@ -140,9 +140,12 @@ struct timespec;
 
 #endif /* __KERNEL__ || __XENO_SIM__ */
 
+#if defined(__KERNEL__) || defined(__XENO_SIM__) || \
+    !define(HAVE_PTHREAD_MUTEXATTR_SETPROTOCOL)
 #define PTHREAD_PRIO_NONE    0
 #define PTHREAD_PRIO_INHERIT 1
 #define PTHREAD_PRIO_PROTECT 2
+#endif /* __KERNEL__ || __XENO_SIM__ || !HAVE_PTHREAD_MUTEXATTR_SETPROTOCOL */
 
 #define PTHREAD_WARNSW     XNTRAPSW
 #define PTHREAD_LOCK_SCHED XNLOCK
@@ -418,17 +421,21 @@ int pthread_intr_control_np(pthread_intr_t intr,
 extern "C" {
 #endif
 
+#ifndef HAVE_PTHREAD_MUTEXATTR_SETPROTOCOL
 int pthread_mutexattr_getprotocol(const pthread_mutexattr_t *attr,
 				  int *proto);
 
 int pthread_mutexattr_setprotocol(pthread_mutexattr_t *attr,
 				  int proto);
+#endif
 
+#ifndef HAVE_PTHREAD_CONDATTR_SETCLOCK
 int pthread_condattr_getclock(const pthread_condattr_t *attr,
 			      clockid_t *clk_id);
 
 int pthread_condattr_setclock(pthread_condattr_t *attr,
 			      clockid_t clk_id);
+#endif
 
 int pthread_make_periodic_np(pthread_t thread,
 			     struct timespec *starttp,