thread-local storage not supported for this target about cello HOT 8 CLOSED

so it looks like threaad local storage isn't supported on OSX due to the executable format - most people suggest implementing your own by tying an object to the creation of threads. I was planning on doing this anyway to make the solution more clean but hadn't gotten around to making a Threads wrapper in Cello. This is probably a good time to start.

from cello.

Hello,

In order to make the Exception objects thread safe, libCello used Thread Local Storage (TLS) to declare some global variable (__thread keyword)

On OSX, Clang/GCC do not support TLS. As @orangeduck says, it's a work in progress.

If you don't want to create multi threads application or use exceptions, I suggest you to remove the __thread keyword

Bertrand

from cello.

@orangeduck Instead of writing our own Thread wrapper, why not using pthread library ?

from cello.

Having tried that: make check then fails with ~19 errors:

error: nested functions are disabled, use -fnested-functions to re-enable

After ./configure CC="gcc -fnested-functions", make fails:

ld: -allow_stack_execute option can only be used when linking a main executable

A few people are raising other issues about post-build problems on OS X. Any chance you can get one of them to contribute a set of build instructions that result in a [vaguely] working library? I don't believe I'll succeed just blundering from error to error.

from cello.

@bcachet That was my intention for posix systems but also would be nice to have winthread supported too. Then both need to wrapped in a Cello like "Thread" type.

from cello.

@garthk please add -fnested-functions to the compile flags inside tests/Makefile.am which will look like this:

check_PROGRAMS = tests

tests_SOURCES = \
  core.c \
  data.c \
  exception.c \
  functional.c \
  memory.c \
  ptest.c \
  test.c

tests_CPPFLAGS = -I$(top_srcdir)/tests
tests_CFLAGS = -std=gnu99 -Wall -Werror -Wextra -Wno-unused -fnested-functions
tests_LDFLAGS = -lCello

TESTS = tests

or add ADD_DEFINITIONS(-fnested-functions) to tests/CMakeLists.txt and use cmake to generate your build environment

Bertrand

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The portable way would be to use libpthread with pthread_getspecific() or use C11's thread.h _Thread_local. But I doubt the last C standard is shipped with OSX... What about ifdefs and wrappers depending on features found?

from cello.

Indeed this is the method I ended up using. Should be fixed in latest commit.

from cello.