threads / patch / 17374

patchmake: By default, remove -pthread on Darwin (it is included by cstdlib).

Subject: [PATCH] make: By default, remove -pthread on Darwin (it is included by cstdlib).

## tl;dr

5 messages between Jan 26, 2009 and Jan 26, 2009. Diffs are folded; open one to read it.

replies: 4people: 2as markdown or json

Ted Pavlic· Jan 26, 2009, 16:26 UTC · lore

As discussed in

http://lists.apple.com/archives/Unix-porting/2005/Mar/msg00019.html

the Mac OS X C standard library is always thread safe and always includes the pthread library. So explicitly using -pthread causes an 'unrecognized option' compiler warning.

This patch clears PTHREAD_LIBS by default. However, if FORCE_DARWIN_PTHREAD_LIBS is defined, then PTHREAD_LIBS will be set as before.

Signed-off-by: Ted Pavlic <ted@tedpavlic.com>
---
 Makefile |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

Show changes to Makefile +12 −0

diff --git a/Makefile b/Makefile
index b4d9cb4..30764af 100644
--- a/Makefile
+++ b/Makefile
@@ -70,6 +70,15 @@ all::
 # specify your own (or DarwinPort's) include directories and
 # library directories by defining CFLAGS and LDFLAGS appropriately.
 #
+#
+# Define FORCE_DARWIN_PTHREAD_LIBS if you are building on Darwin/Mac OS
+# X and want PTHREAD_LIBS to be set. On Mac OS X, all components of the
+# C standard library that are defined to be thread safe by the POSIX
+# standard already include the pthread library. Hence, the -pthread
+# option is redundant and will generate an 'unrecognized option'
+# warning. So PTHREAD_LIBS will be cleared unless
+# FORCE_DARWIN_PTHREAD_LIBS is set.
+#
 # Define PPC_SHA1 environment variable when running make to make use of
 # a bundled SHA1 routine optimized for PowerPC.
 #
@@ -817,6 +826,9 @@ ifeq ($(uname_S),Darwin)
 			BASIC_LDFLAGS += -L/opt/local/lib
 		endif
 	endif
+	ifndef FORCE_DARWIN_PTHREAD_LIBS
+		PTHREAD_LIBS =
+	endif
 endif
 
 ifndef CC_LD_DYNPATH

-- 
1.6.1.213.g28da8

Ted Pavlic· Jan 26, 2009, 16:33 UTC · re: Ted Pavlic · lore

[PATCH (update)] make: By default, remove -pthread on Darwin (it is included by cstdlib).

As discussed in

http://lists.apple.com/archives/Unix-porting/2005/Mar/msg00019.html

the Mac OS X C standard library is always thread safe and always includes the pthread library. So explicitly using -pthread causes an 'unrecognized option' compiler warning.

This patch clears PTHREAD_LIBS by default. However, if FORCE_DARWIN_PTHREAD_LIBS is defined, then PTHREAD_LIBS will be set as before.

Signed-off-by: Ted Pavlic <ted@tedpavlic.com>
---

This update adds the documentation comment in the Makefile to configure.ac as well.

 Makefile     |   11 +++++++++++
 configure.ac |    8 ++++++++
 2 files changed, 19 insertions(+), 0 deletions(-)

Show changes to 2 files +19 −0

Makefile, configure.ac

diff --git a/Makefile b/Makefile
index b4d9cb4..86f0a66 100644
--- a/Makefile
+++ b/Makefile
@@ -70,6 +70,14 @@ all::
 # specify your own (or DarwinPort's) include directories and
 # library directories by defining CFLAGS and LDFLAGS appropriately.
 #
+# Define FORCE_DARWIN_PTHREAD_LIBS if you are building on Darwin/Mac OS
+# X and want PTHREAD_LIBS to be set. On Mac OS X, all components of the
+# C standard library that are defined to be thread safe by the POSIX
+# standard already include the pthread library. Hence, the -pthread
+# option is redundant and will generate an 'unrecognized option'
+# warning. So PTHREAD_LIBS will be cleared unless
+# FORCE_DARWIN_PTHREAD_LIBS is set.
+#
 # Define PPC_SHA1 environment variable when running make to make use of
 # a bundled SHA1 routine optimized for PowerPC.
 #
@@ -817,6 +825,9 @@ ifeq ($(uname_S),Darwin)
 			BASIC_LDFLAGS += -L/opt/local/lib
 		endif
 	endif
+	ifndef FORCE_DARWIN_PTHREAD_LIBS
+		PTHREAD_LIBS =
+	endif
 endif
 
 ifndef CC_LD_DYNPATH
diff --git a/configure.ac b/configure.ac
index 082a03d..a53d97c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -578,6 +578,14 @@ GIT_PARSE_WITH(expat))
 # specify your own (or DarwinPort's) include directories and
 # library directories by defining CFLAGS and LDFLAGS appropriately.
 #
+# Define FORCE_DARWIN_PTHREAD_LIBS if you are building on Darwin/Mac OS
+# X and want PTHREAD_LIBS to be set. On Mac OS X, all components of the
+# C standard library that are defined to be thread safe by the POSIX
+# standard already include the pthread library. Hence, the -pthread
+# option is redundant and will generate an 'unrecognized option'
+# warning. So PTHREAD_LIBS will be cleared unless
+# FORCE_DARWIN_PTHREAD_LIBS is set.
+#
 # Define NO_MMAP if you want to avoid mmap.
 #
 # Define NO_ICONV if your libc does not properly support iconv.

-- 
1.6.1.213.g28da8

Junio C Hamano· Jan 26, 2009, 17:47 UTC · re: Ted Pavlic · lore

Re: [PATCH (update)] make: By default, remove -pthread on Darwin (it is included by cstdlib).

Ted Pavlic <ted@tedpavlic.com> writes:

Show 11 quoted lines

> As discussed in
>
> http://lists.apple.com/archives/Unix-porting/2005/Mar/msg00019.html
>
> the Mac OS X C standard library is always thread safe and always
> includes the pthread library. So explicitly using -pthread causes an
> 'unrecognized option' compiler warning.
>
> This patch clears PTHREAD_LIBS by default. However, if
> FORCE_DARWIN_PTHREAD_LIBS is defined, then PTHREAD_LIBS will be set as
> before.

Why is this even configurable?  You explained pretty clearly that:

 - With -pthread, you get an nasty warning;
 - By default, we now do not use -pthread;
 - By adding FORCE_DARWIN_PTHREAD_LIBS, you can still compile with
   -pthread.

But the above leaves the reader wondering in what situation it may be useful to use FORCE_* and for what purpose other than to get the nasty warning back (which probably is not most users want to).

Ted Pavlic· Jan 26, 2009, 18:57 UTC · re: Junio C Hamano · lore

Re: [PATCH (update)] make: By default, remove -pthread on Darwin (it is included by cstdlib).

...

Show 5 quoted lines

>> This patch clears PTHREAD_LIBS by default. However, if
>> FORCE_DARWIN_PTHREAD_LIBS is defined, then PTHREAD_LIBS will be set as
>> before.
>
> Why is this even configurable?  You explained pretty clearly that:

...

> But the above leaves the reader wondering in what situation it may be
> useful to use FORCE_* and for what purpose other than to get the nasty
> warning back (which probably is not most users want to).

I was afraid that there would be some strange situation where someone would have a configuration where they might want pthreads turned on. I suppose that if someone is in that specialized situation, they will be able to customize their build environment on their own.

I will submit a new patch without the define.

Thanks -- Ted

-- 
Ted Pavlic <ted@tedpavlic.com>

   Please visit my ALS association page:
         http://web.alsa.org/goto/tedpavlic
   My family appreciates your support in the fight to defeat ALS.

Ted Pavlic· Jan 26, 2009, 19:03 UTC · re: Ted Pavlic · lore

[PATCH] make: Remove -pthread on Darwin (it is included by cstdlib).

As discussed in

http://lists.apple.com/archives/Unix-porting/2005/Mar/msg00019.html

the Mac OS X C standard library is always thread safe and always includes the pthread library. So explicitly using -pthread causes an 'unrecognized option' compiler warning.

This patch clears PTHREAD_LIBS if Darwin is detected.

Signed-off-by: Ted Pavlic <ted@tedpavlic.com>
---

Rather than simply clearing PTHREAD_LIBS, would it be better to filter PTHREAD_LIBS to remove "-pthread" if detected?

 Makefile |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

Show changes to Makefile +1 −0

diff --git a/Makefile b/Makefile
index b4d9cb4..9d451cf 100644
--- a/Makefile
+++ b/Makefile
@@ -817,6 +817,7 @@ ifeq ($(uname_S),Darwin)
 			BASIC_LDFLAGS += -L/opt/local/lib
 		endif
 	endif
+	PTHREAD_LIBS =
 endif
 
 ifndef CC_LD_DYNPATH

-- 
1.6.1.213.g28da8