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updated some examples and docs

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Thom Troy
2016-08-17 23:59:46 +01:00
parent 8401b8e4e6
commit dd8f9454de
8 changed files with 97 additions and 33 deletions
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2
01-basic/B-hello-headers/README.adoc
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@@ -86,7 +86,7 @@ file(GLOB SOURCES "src/*.cpp")
## Including Directories
When you have different include folders, you can make your compiler aware of them using the
+target_include_directories()+ function. When compiling this target this will add these directories to the compiler with the -I flag e.g. `-I/directory/path`
+target_include_directories()+ link:https://cmake.org/cmake/help/v3.0/command/target_include_directories.html[function]. When compiling this target this will add these directories to the compiler with the -I flag e.g. `-I/directory/path`
[source,cmake]
----

11
01-basic/C-static-library/README.adoc
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@@ -48,7 +48,16 @@ the sources from the +library_SOURCES+ variable.
## Populating Including Directories
In this example, we include directories in the library using the +target_include_directories()+ function with the scope set to +PUBLIC+. This will cause the included directory used in the following places:
In this example, we include directories in the library using the +target_include_directories()+ function with the scope set to +PUBLIC+.
[source,cmake]
----
target_include_directories(hello_library
PUBLIC ${PROJECT_SOURCE_DIR}/inc
)
----
This will cause the included directory used in the following places:
* When compiling the library
* When compiling any additional target that links the library.

5
01-basic/D-shared-library/README.adoc
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@@ -33,7 +33,6 @@ $ tree
## Adding a Shared Library
As with the previous example on static libraries, the +add_library()+ function
is also used to create a shared library from some source files.
This is called as follows:
@@ -52,14 +51,14 @@ the sources from the +library_SOURCES+ variable.
## Alias Target
As the name suggests an alias target is an alternative name for a target that can be used instead of the real target name in read-only contexts.
As the name suggests an link:https://cmake.org/cmake/help/v3.0/manual/cmake-buildsystem.7.html#alias-targets[alias target] is an alternative name for a target that can be used instead of the real target name in read-only contexts.
[source,cmake]
----
add_library(hello::library ALIAS hello_library)
----
As show below, this allows you to reference the target using the alias name when linking it against other targets.
As shown below, this allows you to reference the target using the alias name when linking it against other targets.
## Linking a Shared Library

52
01-basic/G-compile-flags/README.adoc
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@@ -6,8 +6,10 @@ toc::[]
# Introduction
CMake supports setting compile flags using the +CMAKE_C_FLAGS+ and +CMAKE_CXX_FLAGS+
variables. Similarly linker flags can be set using the +CMAKE_LINKER_FLAGS+.
CMake supports setting compile flags in a number of different ways:
* using +target_compile_definitions()+ function
* using the +CMAKE_C_FLAGS+ and +CMAKE_CXX_FLAGS+ variables.
The files in this tutorial are below:
@@ -23,22 +25,24 @@ $ tree
# Concepts
# Set Per-Target C++ Flags
## Set C++ Flag
Similar to the build type a global C++ compiler flag can be set using the following methods.
- Using a gui tool such as ccmake / cmake-gui
image::cmake-gui-set-cxx-flag.png[cmake-gui set cxx flag]
- Passing into cmake
The recommended way to set C++ flags in modern CMake is to use per-target flags which can be populated to other targets
through the +target_compile_definitions()+ link:https://cmake.org/cmake/help/v3.0/command/target_compile_definitions.html?highlight=target_compile_definitions[function]. This will populate the link:https://cmake.org/cmake/help/v3.0/prop_tgt/INTERFACE_COMPILE_DEFINITIONS.html#prop_tgt:INTERFACE_COMPILE_DEFINITIONS[INTERFACE_COMPILE_DEFINITIONS] for the library and push the definition to the linked target depending on the scope.
[source,cmake]
----
cmake .. -DCMAKE_CXX_FLAGS="-DEX3"
target_compile_definitions(cmake_examples_compile_flags
PRIVATE EX3
)
----
This will cause the compiler to add the definition +-DEX3+ when compiling the target.
In the target was a library, and the scope +PUBLIC+ or +INTERFACE+ has been choosen the definition would also be included in any targets that link this target.
For compiler options you can also use the +target_compile_options()+ link:https://cmake.org/cmake/help/v3.0/command/target_compile_options.html[function].
## Set Default C++ Flags
The default `CMAKE_CXX_FLAGS` is either empty or contains the appropriate flags
@@ -52,6 +56,11 @@ top level CMakeLists.txt
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DEX2" CACHE STRING "Set C++ Compiler Flags" FORCE)
----
Similarly to +CMAKE_CXX_FLAGS+ other options include:
* Setting C compiler flags using +CMAKE_C_FLAGS+
* Setting linker flags using +CMAKE_LINKER_FLAGS+.
[NOTE]
====
The values `CACHE STRING "Set C++ Compiler Flags" FORCE` from the above command
@@ -60,19 +69,24 @@ are used to force this variable to be set in the CMakeCache.txt file.
For more details, see https://cmake.org/cmake/help/v3.0/command/set.html[here]
====
## Set Per-Target C++ Flags
Once set the +CMAKE_C_FLAGS+ and +CMAKE_CXX_FLAGS+ will set a compler flag / definiton globally for all targets in this directory or any included sub-directories. To set a compiler definitons for a specific target you can use the +target_compile_defintions()+ link:https://cmake.org/cmake/help/v3.0/command/target_compile_definitions.html[function]. This will cause the compiler to add the definition +-DEX3+ when compiling the target.
Once set the +CMAKE_C_FLAGS+ and +CMAKE_CXX_FLAGS+ will set a compler flag / definiton globally for all targets in this directory or any included sub-directories. This method is not recommended for general usage now and the +target_compile_definitions+ function is preferred.
### Set CMake Flags
Similar to the build type a global C++ compiler flag can be set using the following methods.
- Using a gui tool such as ccmake / cmake-gui
image::cmake-gui-set-cxx-flag.png[cmake-gui set cxx flag]
- Passing into cmake
[source,cmake]
----
target_compile_defintions(cmake_examples_compile_flags
PRIVATE EX3
)
cmake .. -DCMAKE_CXX_FLAGS="-DEX3"
----
Depending on the scope this defintion may also be included in any targets that link this target. For compiler options you can also use the +target_compile_options()+ link:https://cmake.org/cmake/help/v3.0/command/target_compile_options.html[function].
# Building the Example
[source,bash]

13
01-basic/H-third-party-library/CMakeLists.txt
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@@ -1,11 +1,11 @@
cmake_minimum_required(VERSION 3.0)
cmake_minimum_required(VERSION 3.4)
# Set the project name
project (third_party_include)
# find a boost install with the libraries filesystem and system
find_package(Boost 1.46.1 REQUIRED COMPONENTS filesystem system)
find_package(Boost REQUIRED COMPONENTS filesystem system)
# check if boost was found
if(Boost_FOUND)
@@ -18,13 +18,12 @@ endif()
add_executable(third_party_include main.cpp)
# Include the boost headers
target_include_directories( third_party_include
PRIVATE ${Boost_INCLUDE_DIRS}
)
#target_include_directories( third_party_include
# PRIVATE Boost::boost
#)
# link against the boost libraries
target_link_libraries( third_party_include
PRIVATE
${Boost_SYSTEM_LIBRARY}
${Boost_FILESYSTEM_LIBRARY}
Boost::filesystem
)

21
01-basic/H-third-party-library/README.adoc
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@@ -91,6 +91,27 @@ The variables exported in this example include:
In some cases you can also check these variables by examining the cache using
ccmake or cmake-gui.
## Alias variables
Some modern CMake libraries export +ALIAS+ targets in their module files. For example, starting in later versions of CMake (v3.5+),
Boost uses this. +ALIAS+ targets make referencing found targets eaiser. This is similar to using your own alias targets for libraries.
In the case of Boost, you could replace the following from this example:
* `Boost_INCLUDE_DIRS` with `Boost::boost` for header only libraries
* `Boost_FILESYSTEM_LIBRARY` with `Boost::filesystem`
* `Boost_SYSTEM_LIBRARY` with `Boost::system`. If you include `Boost::filesystem` it automatically includes `Boost::system`
Using the new alias sytem, to replicate this example you only have to link the following:
[source,cmake]
----
target_link_libraries( third_party_include
PRIVATE
Boost::filesystem
)
----
# Building the Example
[source,bash]

24
README.adoc
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@@ -18,16 +18,20 @@ more complex use cases.
These examples have been tested on Ubuntu 14.04 but should work under any Linux system that supports CMake.
This branch works with the CMake version 3.x onwards. For examples that use CMake version 2.x see the branch link:https://github.com/ttroy50/cmake-examples/tree/v2-style-includes[v2-style-includes].
image:https://travis-ci.org/ttroy50/cmake-examples.svg?branch=master["Build Status", link="https://travis-ci.org/ttroy50/cmake-examples"]
# Requirements
The basic requirements for most examples are:
* CMake
* CMake v3.x
* A c++ compiler (defaults to gcc)
* make
## Installation on Ubuntu
The easiest way to install the above on Ubuntu is as follows
[source,bash]
@@ -59,11 +63,29 @@ Some specific examples may require other tools including:
$ sudo apt-get install ninja-build
## Docker
Docker container will all requirements and different versions of CMake are generated to help make testing the examples easier. These are available from the docker hub repository link:https://hub.docker.com/r/matrim/cmake-examples/[matrim/cmake-examples].
To build the full set of cmake-examples test cases you can run:
[source,bash]
----
docker run -it matrim/cmake-examples:3.4.3
git clone https://github.com/ttroy50/cmake-examples.git
cd cmake-examples
./test.sh
----
For more details on build and running the docker containers link:here[dockerfiles].
# Other Links
There are many CMake tutorials and examples online. The list below includes links
to some of these which I have found helpful in my CMake journey.
* http://www.kdab.com/~stephen/moderncmake.pdf[Modern CMake Slides]
* https://rix0r.nl/blog/2015/08/13/cmake-guide/[rix0r Modern CMake Blog]
* https://cmake.org/cmake-tutorial/[Official CMake Tutorial]
* https://cmake.org/Wiki/Main_Page[Official CMake Wiki]
* https://cmake.org/Wiki/CMake_Useful_Variables[CMake Useful Variables]

2
test.sh
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@@ -9,7 +9,7 @@ cmake --help
EXAMPLES_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
echo "running examples in $EXAMPLES_DIR"
cd $EXAMPLES_DIR
cd $EXAMPHLES_DIR
dirs=( ./01-basic/A-hello-cmake \
./01-basic/B-hello-headers \