library versioning with cmake - cmake

I have a project with 4 different sub projects. To specify the versions, I use the
SET(parent_VERSION_MAJOR 1)
SET(parent_VERSION_MINOR 0)
set(parent_VERSION_PATCH 0)
set(parent_VERSION 1.0.0)
and then I can use this in the sub projects if the add_subdirectory is used.
Q1. I could not set parent_VERSION based on MAJOR, MINOR and PATCH. According to the documentation is should be set automatically but whenever I try printing it, it is empty without using the last line in the code.
Q2. In case I want to build from sub directory only, I get an error shouting :
CMake Error at CMakeLists.txt:28 (set_target_properties):
set_target_properties called with incorrect number of arguments.
which is because I am using parent_VERSION there.
So I understand that it isn't able to get the parent_VERSION without running cmake from the top directory but how do I change the code such that it can build even without running from the top level.
I read about SET with INHERITED but I don't think that is what I need.

Here is how I solved it. If someone could tell me a better/more elegant way I'd be happy.
if(NOT parent_VERSION)
SET(parent_VERSION_MAJOR 1)
SET(parent_VERSION_MINOR 0)
SET(parent_VERSION_PATCH 0)
SET(parent_VERSION 1.0.0)
endif(NOT parent_VERSION)

Related

Successful build of Kicad 4.0.6 in Linux Mageia 5 via fixing a wx-3.0 symbol

I have managed to build the Kicad 4.0.6 in Linux Mageia 5.1 with gcc version 4.9.2. I first manually fixed two wxWidgets 3.0.2 header files in the /usr/include/wx-3.0/wx/ directory: regex.h and features.h. Kicad then compiled successfully. With the native wx-3.0 headers, the compiler generated the error in pcbnew/netlist_reader.cpp due to the undefined variable wxRE_ADVANCED.
The features.h header checks if the macro WX_NO_REGEX_ADVANCED is defined. If yes, features.h UNdefines wxHAS_REGEX_ADVANCED macro, and defines it, if no. The macro wxHAS_REGEX_ADVANCED, in turn, is used in regex.h to determine if among the enum constants wxRE_ADVANCED = 1 is present. The standard prebuilt Mageia 5 packages wxgtku3.0_0 and lib64wxgtku3.0-devel that I installed with the use of Mageia's software manager urpmi from Mageia repository WX_NO_REGEX_ADVANCED is defined, therefore wxHAS_REGEX_ADVANCED is undefined, and, hence, wxRE_ADVANCED is undefined either. Kicad 4.0.6 source package assumes wxRE_ADVANCED = 1, therefore the build process stops with the error.
Then I reverted /usr/include/wx-3.0/wx/regex.h and features.h to their original state and learned how to add the definition of wxRE_ADVANCED to CMakeLists.txt. However, I still have a question.
The recommended format of adding the definition to CMakeLists.txt I found at CMake command line for C++ #define is this:
if (NOT DEFINED wxRE_ADVANCED)
set(wxRE_ADVANCED 1)
endif()
add_definitions(-DwxRE_ADVANCED=$(wxRE_ADVANCED))
However, it did not work! The macro expansion for wxRE_ADVANCED in pcbnew/netlist_reader.cpp was empty. I printed it at compile time inserting the following lines into the netlist_reader.cpp file (this was hard to find, most of the recommended formats did not work. The correct one is in C preprocessor: expand macro in a #warning):
#define __STRINGIFY(TEXT) #TEXT
#define __WARNING(TEXT) __STRINGIFY(GCC warning TEXT)
#define WARNING(VALUE) __WARNING(__STRINGIFY(wxRE_ADVANCED = VALUE))
Pragma (WARNING(wxRE_ADVANCED))
Finally, I simplified the CMakeLists.txt definition down to this, and it was a success:
if (NOT DEFINED wxRE_ADVANCED)
set(wxRE_ADVANCED 1)
endif()
add_definitions(-DwxRE_ADVANCED=1)
My question: what is the meaning of "-DwxRE_ADVANCED=$(wxRE_ADVANCED)" if it does not work? Is it possible not to use set(wxRE_ADVANCED 1), and simply write add_definitions(-DwxRE_ADVANCED=1)? Thank you.
P.S. Yes, the Kicad 4.0.6 build process successfully finished with only one line added to the top level CMakeLists.txt file:
add_definitions(-DwxRE_ADVANCED=1)
A variable is called via $variable or ${variable}. Note the curly brackets, not parentheses.
Also, it is recommended to use:
target_compile_definitions(mytarget PUBLIC wxRE_ADVANCED=1)
on a target directly, rather than the general add_definitions() command.

How can a CMake variable be hidden?

I have a CMake project which lets a globally set variable (set with -DARDUINO_SDK_PATH=/a/b/c on command line) disappear i.e. suddenly the given value is gone which leads to a fatal error.
I know there are different ways to "hide" a variable (e.g. inside functions or external projects)
In my case:
the variable is not being set explicitly anywhere in the code (e.g. via set() or find_path())
the access which leads to the error is on top level (i.e. not inside a function)
there are instructions (i.e. same file/line) where in one case the variable has the value it's been given and the next time it's gone
Tracing the variable with variable_watch(ARDUINO_SDK_PATH) I can see that everything works fine before the compiler is being checked:
cmake -DARDUINO_SDK_PATH=/a/b/c <path>
...
... everything fine, ${DARDUINO_SDK_PATH} == '/a/b/c' everywhere
...
-- Check for working C compiler: /usr/bin/avr-gcc
...
... here the variable is empty and not being traced any more
...
Here is my suggestion:
Does the compiler check (indicated by check for working C compiler .. on the terminal) have it's own variable space and does not know variables provided on command line?
Note: This question is a generalization of this question, which has become way too specialized but might offer some useful background information.
That any modification to variable is not traced after the variable_watch() command seems like a bug somewhere in CMake to me.
Generally speaking a "cached CMake variable" can be hidden by a "normal CMake variable" with the same name. But e.g. find_path() won't run again or modify a variable if already set.
Here is an example:
cmake_minimum_required(VERSION 2.4)
project(VariableWatchTest NONE)
variable_watch(MY_TEST_VAR)
set(MY_TEST_VAR "something" CACHE INTERNAL "")
message("${MY_TEST_VAR}")
set(MY_TEST_VAR "hiding something")
message("${MY_TEST_VAR}")
unset(MY_TEST_VAR)
message("${MY_TEST_VAR}")
find_path(MY_TEST_VAR NAMES "CMakeLists.txt" HINTS "${CMAKE_CURRENT_LIST_DIR}")
message("${MY_TEST_VAR}")
Would give (without the variable_watch() messages:
-- something
-- hiding something
-- something
-- something
References
What's the CMake syntax to set and use variables?
I'm not sure whether this is a bug or a feature but (at least some) CMake variables are not available in certain steps of the CMake configuration procedure.
You can check this by adding something like this to your toolchain file:
MESSAGE("FOO: ${FOO}")
and run CMake like this
cd build-dir
cmake -DFOO=TEST ..
You will likely see FOO printed with value TEST once in the beginning of the configuration process and later printed again but being empty.
Just don't access variables from the global space inside a toolchain file (doesn't belong there anyway).

CMake - set_property could not find CACHE variable

Disclaimer: I'm aware of this question. However, The OP's needs are different to mine: what he actually wants is to port an app to Linux and therefore the answers go in that line, not answering what I want to know: the reasons of the error.
I'm trying to create a dropdown list in CMake GUI following the instructions in here and here
So I have this very simple CMakeLists.txt:
cmake_minimum_required(VERSION 3.6)
project(datasetprograms)
set(CMAKE_CXX_STANDARD 11)
#LINES TO MAKE THE GUI DROP-DOWN:
set(TARGET_ARCHITECTURE “arm” CACHE STRING “Architecture to compile to”)
set_property(CACHE TARGET_ARCHITECTURE PROPERTY STRINGS arm x86)
#Add subdirectories for each project
add_subdirectory(helloworld)
Basically I just copied and pasted, following the instructions. However, instead of having a nice drop-down in the CMake GUI, I got the following error:
CMake Error at CMakeLists.txt:9 (set_property): set_property could
not find CACHE variable TARGET_ARCHITECTURE. Perhaps it has not yet
been created
Question: What I'm doing wrong?
You may check value of variable TARGET_ARCHITECTURE using message() and you will found CACHE is a part of that value.
This is because you use in set() command double quotes which are not common ones (") but language-specific (“). So CMake treats set() command as not CACHE'd one. That is a reason of the error message.

How to idiomatically set the version number in a CMAKE/CPACK project?

I'm trying to edit the CPack settings so that the outputted package file has the correct version number in it. But that's not all. I'd like CMake/CPack to have all the places where the version number is updated also be set. The .so file should also be set. And whatever else needs it.
From where I sit, the CPack documentation appears to be telling us to repeat ourselves.
If I do nothing, the output file is like so:
mystuff-0.1.1-Linux.tar.gz
Let's say the version number should be 1.2.3.
I would think that this is the minimalistic CPACK settings to cause all the version numbers to be changed -- and I placed these lines in my CMakeLists.txt file:
SET(CPACK_PACKAGE_DESCRIPTION_SUMMARY "My app is great")
SET(CPACK_PACKAGE_VENDOR "My Name")
SET(CPACK_PACKAGE_DESCRIPTION_FILE "${CMAKE_CURRENT_SOURCE_DIR}/README.md")
SET(CPACK_RESOURCE_FILE_LICENSE "${CMAKE_CURRENT_SOURCE_DIR}/LICENSE")
SET(CPACK_PACKAGE_VERSION_MAJOR "1")
SET(CPACK_PACKAGE_VERSION_MINOR "3")
SET(CPACK_PACKAGE_VERSION_PATCH "2")
When I build, the output file is still mystuff-0.1.1-Linux.tar.gz
If I repeat myself and do this:
SET(CPACK_PACKAGE_VERSION "${CPACK_PACKAGE_VERSION_MAJOR}.${CPACK_PACKAGE_VERSION_MINOR}.${CPACK_PACKAGE_VERSION_PATCH}")
Now that variable is set, but the file is still mystuff-0.1.1-Linux.tar.gz
It seems that I must also change CPACK_PACKAGE_FILE_NAME
What other places do I have to re-state the version number?
This doesn't feel idiomatic. I must be missing something to make this automatic. Am I supposed to specify the variable at an earlier point in time? I also see some projects on the internet containing a CPackConfig.cmake file -- the file contains overrides, but I still see some repeating oneself going on in those as well.
This bug also mentions the same thing. Apparently, they do want us to repeat ourselves. (as of 2015) However, even if that is the case, I was wondering if anyone has found a work-around?
If no work around, how about a way to re-state all the variables so that they end up automatically set correctly? For instance, doing the following is a way to compose the version number by using the variables
SET(CPACK_PACKAGE_VERSION "${CPACK_PACKAGE_VERSION_MAJOR}.${CPACK_PACKAGE_VERSION_MINOR}.${CPACK_PACKAGE_VERSION_PATCH}")
According to the documentation, the file name is composed like this:
SET(CPACK_PACKAGE_FILE_NAME "${CPACK_PACKAGE_NAME}-${CPACK_PACKAGE_VERSION}-${CPACK_SYSTEM_NAME}")
There are probably other variables that need re-setting. If I have to restate everything, then exactly what do I need to restate to be complete?
Make sure that you have the following line after setting the CPACK_... variables:
include (CPack)
This is the spot where CPACK_PACKAGE_FILE_NAME and others are automatically set, so the version variables (such as CPACK_PACKAGE_VERSION_MAJOR) must be already set at this point.
If you set your project's version via https://cmake.org/cmake/help/v3.0/command/project.html, you can set the cpack version like
set(CPACK_PACKAGE_VERSION_MAJOR ${PROJECT_VERSION_MAJOR})
set(CPACK_PACKAGE_VERSION_MINOR ${PROJECT_VERSION_MINOR})
set(CPACK_PACKAGE_VERSION_PATCH ${PROJECT_VERSION_PATCH})
include(CPack)
You'll probably want to look at the documentation for the PROJECT() command, which has a VERSION field. I'm not sure if it is wired through to CPack, but at least that is the idiomatic place for setting the project version.
https://cmake.org/cmake/help/v3.0/command/project.html

Proper way to call a found executable in a custom command?

I have a program on my computer, let's say C:/Tools/generate_v23_debug.exe
I have a FindGenerate.cmake file which allows CMake to find that exact path to the executable.
So in my CMake code, I do:
find_program(Generate)
if (NOT Generate_FOUND)
message(FATAL_ERROR "Generator not found!")
So CMake has found the executable. Now I want to call this program in a custom command statement. Should I use COMMAND Generator or COMMAND ${GENERATOR_EXECUTABLE}? Will both of these do the same thing? Is one preferred over the other? Is name_EXECUTABLE a variable that CMake will define (it's not in the FindGenerate.cmake file), or is it something specific to someone else's example code I'm looking at? Will COMMAND Generator be expanded to the correct path?
add_custom_command(
OUTPUT blahblah.txt
COMMAND Generator inputfile1.log
DEPENDS Generator
)
find_program stores its result into the variable given as a first argument. You can verify this by inserting some debug output:
find_program(GENERATOR Generate)
message(${GENERATOR})
Note that find_program does not set any additional variables beyond that. In particular, you mentioned Generate_FOUND and GENERATOR_EXECUTABLE in your question and neither of those gets introduced implicitly by the find_program call.
The second mistake in your program is the use of the DEPENDS option on the add_custom_command. DEPENDS is used to model inter-target dependencies at build time and not to manipulate control flow in the CMakeLists. For example, additional custom command can DEPEND on the output of your command (blahblah.txt), but a custom command cannot DEPEND on the result of a previous find operation.
A working example might look something like this:
find_program(GENERATOR Generate)
if(NOT GENERATOR)
message(FATAL_ERROR "Generator not found!")
endif()
add_custom_command(
OUTPUT blahblah.txt
COMMAND ${GENERATOR} inputfile1.log
)
P.S.: You asked why the code examples were not properly formatted in your question. You indented everything correctly, but you need an additional newline between normal text and code paragraphs. I edited your question accordingly.