CMake: per configuration dependencies - visual-studio

In CMake, is it possible to make target dependencies specific to a particular configuration?
My structure is an executable, which can be built with different backend renderers, one OpenGL and the other D3D. The backend renderers have their own (static) libraries, and only one library should be linked in, based on the configuration (eg. GL_Debug, D3D_Debug, etc). However, it doesn't seem as though the add_dependency command has any options for per-configuration settings.
My current solution is to use generation configurations (Debug, Release, etc), and an option to select the renderer type, and regenerate the solution if I'd like to switch. However, this is clunky if I want to switch between the two frequently. Ideally, I would have a solution with all the renderer configurations, and could just switch between them in Visual Studio.

target_link_libraries command may link in configuration-dependent way. Alternatively, generator-expressions can be used for LINK_LIBRARIES property for executable/library.

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Multiple Metal shaders with different language versions in one project

I'm trying to include multiple Metal shaders in my Xcode project which have different language versions, but I'm unable to figure out how to do it.
I'm trying to do this, so I can support the latest features when available and drop back when not.
In the project's settings I can only find a general specifier for the Metal language revision. I also can't find anything in the MSL reference manual to specify it inside the file.
Is this even possible? If so, how?
Thanks in advance.
In Xcode, go to the Build Phases for the target which builds your app. Disclose the compile sources. Select a .metal file. Double-click in the right-hand Compiler Flags column to edit it. Enter -std=osx-metal1.2 or similar. That specific shader source file will be compiled with that language.
I found this compiler flag by comparing the build transcripts of builds with various settings for the target-wide build setting.

How can I force Xcode to use a custom compiler?

I want to force Xcode to use a custom compiler ('clang-llvm' build from the src) so I can use the clang plugin. My Xcode version is 7.3.1.
People say it is possible with custom toolchains. I didn't make a research on them because easier solution worked well for me:
It is also possible to run frontend plugins directly by setting appropriate "build settings" of Xcode. (Several ways to do this, you can set them on the command line for instance: xcodebuild build FOO=bla.) Here are a few build settings that I found useful to inject C flags:
OTHER_CFLAGS, OTHER_CPLUSPLUSFLAGS or to replace the compiler(s) and linker(s):
CC, CPLUSPLUS, LD, LDPLUSPLUS, LIBTOOL
The same approach works to control the "analyze" action: CLANG_ANALYZER_EXEC, CLANG_ANALYZER_OTHER_FLAGS
Disclaimer: some of those build settings are undocumented (afaik). Use at your own risk.
(Taken from [cfe-dev] Compile/refactor iOS Xcode projects)
For me it was enough to define the following User-Defined Settings in Build Settings of Xcode projects:
CC=my-c-compiler
CXX=my-cxx-compiler
LIBTOOL=my-linker-for-static-libraries
If you use CMake, the way to inject your compiler automatically is to use
set_target_properties(your-target PROPERTIES XCODE_ATTRIBUTE_CC "${YOUR_CC}")
set_target_properties(your-target PROPERTIES XCODE_ATTRIBUTE_CXX "${YOUR_CXX}")
Couple of years ago I've written an article that addresses exactly the problem you describe: Creating and using Clang plugin with Xcode
To enable custom clang you need to actually patch internals of Xcode.app itself, it is technically doable but:
it will break when you update Xcode
it will work correctly on your machine
the version of a plugin and your compiler should match, i.e.
they should be compiled using the same tree
So in general it doesn't really scale, so be careful :)
There's a somewhat obscure feature of Xcode where it supports "alternative toolchains". For example, Swift.org provides installable toolchains for Swift built from current sources.
Unfortunately, while Apple's documentation describes how to install and use such alternative toolchains, it doesn't describe how to create them. There are scripts in the Swift source base which build a toolchain and you can look at them to figure out how it's done. They are in https://github.com/apple/swift/tree/master/utils. Start at build-toolchain, which calls build-script and go from there.
Method 1: Change the User Defined settings
Under the project or target Build Settings add the User Defined settings for
CC=/path/to/cc
CXX=/path/to/c++
This is useful if you have a single compiler or linker you want to call, or if you want to call out to a trampoline that decides what to call on the fly.
Method 2: Create a complete custom toolchain via plugin
Using Clang LLVM 1.0.xcplugin as a template (found in the Xcode.app plugins folder), you can modify the plist to point at your own alternative compiler and linker.
This OLLVM on iOS tutorial walks through it.
From project setting go to build setting with target selected. then select All beside the Basic from the top bar. then under build option you can see the compiler option.
Refer below screenshot,
Update :
I think you should refer Using C and C++ in an iOS App with Objective-C++ and this tutorial.

How to enter custom GCC compiler option in Build Options

There seem to a variety of questions like this one without any clear solution that is true for Xcode 7 (or even other versions of Xcode).
I have a version of GCC that I'd like Xcode to use when it compiles. It is not the standard GCC but customized for a different platform. I can specify and use this compiler fine in Eclipse, but would rather use Xcode. The Build Options only list LLVM and nothing else. When I try to add via "other" in that section, all I get is this empty popup:
What goes in this box? I would think that it should be no big deal for Xcode to simply use a GCC that I have available at a specific path on my system, but this appears to be quite complex.
Update: Apparently there is a supported mechanism for installing externally-provided tool chains in Xcode that I wasn't aware of. For example, one can download packages from swift.org that install alternative tool chain packages into /Library/Developer/Toolchains or ~/Library/Developer/Toolchains. Once one of those is installed, Xcode has a GUI option to switch the active tool chain.
There was a recent change to the Swift sources to include a script for building one's own custom tool chain from them.
If you view the Quick Help for that build setting (View > Utilities > Show Quick Help Inspector) or configure the build settings view to show setting names instead of titles (Editor > Show Setting Names), you'll see that that setting is GCC_VERSION.
If you look that up in the Build Settings Reference, you find:
GCC_VERSION
Description:
Numeric identifier. Identifies the GCC version to be used to compile
the target’s source files. When the target’s “System C rule” is set to
GCC System Version (instead of a specific version number), this build
setting is not available in Run Script build phases.
Values:
2.95.2
3.1
3.3
4.0
Default value:
GCC system version.
Specified in:
Project Info > Rules > “System C rule.”
Target Info > Rules > “System C rule.”
Affects:
GCC_VERSION_IDENTIFIER.
That's actually a bit out of date. It says it's specified by fiddling with a build rule (not setting) called the "System C rule". You used to change the version there but now there's a direct build setting for it.
Anyway, this probably doesn't help you do what you want to do. I doubt there's any value you could put in there that would do something useful, let alone use a third-party compiler.
However, the explanation does have a hint. It mentions the System C build rule. You could modify the build rules on the Build Rules tab of the target configuration screen. You can find the System C rule and press the button to copy it to your target, which will let you specify a custom script to process C files (including Objective-C and C++).
Implementing such a script is non-trivial. The inputs, expected outputs, and required behavior of the script are not well documented. There are various environment variables available for the use of such a script. Some are the build settings. You'll need to translate the relevant settings into compiler options. For example, translate the CLANG_WARN_BOOL_CONVERSION setting into the corresponding -Wbool-conversion option.
Some of the other environment variables indicate which file you should operate on, such as INPUT_FILE_PATH, INPUT_FILE_NAME, etc.
You need to tell Xcode what file(s) your rule outputs. These can be based on the input environment variables/settings, such as $(OBJECT_FILE_DIR)-$(CURRENT_VARIANT)/$(CURRENT_ARCH)/$(INPUT_FILE_BASE).o.
In general, this is just not something that Xcode makes easy.
Someone wrote a plugin that will allow you to use gcc from Xcode.
http://hamelot.io/programming/add-gcc-compiler-to-xcode-6/
If you have a custom gcc then you would need to change the paths around etc but the plugin should work.

cmake visual studio use different configuration by library

I'm trying to use differents configurations for multi-library use.
I explain : i have to use many library for one solution, but i need to change the configuration for each library target, for a debug use of my solution some library will be in 'debug' mode but some other needs a 'Render' configuration. (It's 3rdParty project i can't edit them)
I want to know if its possible.
Thanks !
Here an example the result i wanted to have :
http://i48.tinypic.com/mtugqf.png
You can almost do this. CMake allows for extra configurations by setting CMAKE_CONFIGURATION_TYPES, so in your case this would be
set(CMAKE_CONFIGURATION_TYPES "${CMAKE_CONFIGURATION_TYPES};Render" CACHE STRING "" FORCE)
This needs to be after the project command.
However, this adds a new configuration type to all targets. I don't think CMake has the ability to mix different configurations for individual targets. You'd still have to manually modify the specific libraries' configs via the Configuration Manager once CMake had created the .sln.

library examples build in eclipse

I have C project of a library (using CDT). Configurations for both static and dynamic linking for several platforms. Several examples of the library usage is also included in the project. What is the best way to build these examples with the library? If I would like to build both the library and examples (linking the library just built) in one configuration?
I suppose I have to use custom makefile. Do I have to create makefile for the whole project (several of them, one for each platform), or is there any way how to include examples makefile to the automatic one?
Each example has only one source file, so the only things I need to do in my makefile are to determine which compiler is used, add some flags and link with the library which was built (I would include the make examples command as the post-build step).
As I didn't find any solution for this, I use custom makefile for the whole build. I also found a nice advice somewhere: if you want advanced build functions, use advanced build system.

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