[package] boost/*: ios variant misses two define exports

Package and Environment Details (include every applicable attribute)

• Package Name/Version: boost/1.74.0
• Operating System+version: iOS
• Compiler+version: clang 12
• Conan version: conan 1.31.0
• Python version: Python 3.8.5

Conan profiles

build.profile

[settings]
os=Macos
os_build=Macos
arch=x86_64
arch_build=x86_64
compiler=apple-clang
compiler.version=12.0
compiler.libcxx=libc++
build_type=Release
[options]
[build_requires]
[env]

host.profile (ios Simulator)

[settings]
os=iOS
os.version=12.0
arch=x86_64
compiler=apple-clang
compiler.version=12.0
compiler.libcxx=libc++
build_type=Debug
[options]
[build_requires]
[env]

Steps to reproduce

I’m cross compiling boost from MacOS to iOS Simulator (x86_64). Which works quite well. Awesome job! However when consuming the library weird runtime crashes occur due to invalid memory access. Two days of debugging and address sanitizer showed that the consuming product has two defines missing. -DBOOST_SP_USE_PTHREADS and -DBOOST_AC_USE_PTHREADS.

https://github.com/conan-io/conan-center-index/blob/d956a467dab31503f0054face5c09f83b7a05f68/recipes/boost/all/conanfile.py#L764-L767

May I suggest that you add the flags -DBOOST_SP_USE_PTHREADS and -DBOOST_AC_USE_PTHREADS to the package_info method? https://github.com/conan-io/conan-center-index/blob/d956a467dab31503f0054face5c09f83b7a05f68/recipes/boost/all/conanfile.py#L1014

Thanks for your time!

[madebr]

I’m just saying that the upstream project needs to be made aware of the problem. They know their code the best.

[madebr]

Sounds good, I will add

def package_info(self):
--- a/recipes/boost/all/conanfile.py
+++ b/recipes/boost/all/conanfile.py
@@ -1245,3 +1245,10 @@
                         self.cpp_info.components["_libboost"].cxxflags.append("-pthread")
                         self.cpp_info.components["_libboost"].sharedlinkflags.extend(["-pthread","--shared-memory"])
                         self.cpp_info.components["_libboost"].exelinkflags.extend(["-pthread","--shared-memory"])
+            elif self.settings.os == "iOS":
+                if self.options.multithreading:
+                    # https://github.com/conan-io/conan-center-index/issues/3867
+                    # runtime crashes occur when using the default platform-specific reference counter/atomic
+                    self.cpp_info.components["headers"].extend(["BOOST_AC_USE_PTHREADS", "BOOST_SP_USE_PTHREADS"])
+                else:
+                    self.cpp_info.components["headers"].extend(["BOOST_AC_DISABLE_THREADS", "BOOST_SP_DISABLE_THREADS"])

to the pr at #3872