Re: [boost] cmake target and binary name mangling

Subject: Re: [boost] cmake target and binary name mangling
From: Roger Leigh (rleigh_at_[hidden])
Date: 2017-07-24 20:27:10

On 24/07/17 21:07, Niall Douglas via Boost wrote:
>> Yea, I dont think we should mangle the logical target name at all. The user
>> should be able to write `target_link_libraries(lib boost::foo)` and that
>> should work for either static, shared, or header-only. Supporting multiple
>> variants like shared and static in the same build tree are not supported with
>> cmake, and creating workarounds to try and support them in the same build tree
>> just creates problems. To build shared and static requires two build
>> directories with cmake.
> 
> This is provably untrue.

It's entirely correct if you read what he was saying carefully.

If you use a single target name "lib", this will be a shared library or 
a static library depending upon the build configuration (the 
BUILD_SHARED_LIBS option), or a header-only library.

Supporting shared and static simultaneously isn't possible *with a 
single target name*.  You would have to have e.g. "lib" and 
"lib-static".  And on of the libraries e.g. the static library would 
need a mangled name since on Windows both the import library and the 
static library have a .lib extension and would clash with each other. 
Doing that is possible, but bad practice.  The target names are mangled 
and not as usable downstream; downstream use has to commit to specific 
variants, and it's a lot less flexible.  Choosing shared or static at 
configure time is the way cmake is designed to work, and it's the better 
choice here.  (I have gone with the lib+list-static approach in the past 
and regretted it later.)

Using normal fixed target names does not preclude mangling the binary 
name, which can be set independently as a target property.

Roger