In Go, filenames have semantic meaning. For example:
*_windows.go // Only include in compilations for Windows
*_unix.go // Only include in compilations for Unix
*_386.go // Only include in compilations for 386 systems
*_test.go // Only include when run with `go test`
However, I can't seem to get the following to work:
*_windows_test.go // Only include when running `go test` on windows
*_test_windows.go // Another attempt
Is this even possible with Go? If so, how?
Just use a build constraint on the test files.
// +build windows
A build constraint is evaluated as the OR of space-separated options; each option evaluates as the AND of its comma-separated terms; and each term is an alphanumeric word or, preceded by !, its negation. That is, the build constraint:
Turns out I was wrong. It does work. The issue was that I also had a file called foo_unix_test.go, and apparently Go doesn't support the *_unix.go syntax as a special case.
Related
I've got the following generator expression working, which sets the /GS flag if the compiler is MSVC and it sets it for the build configurations RelWithDebInfo and Release:
target_compile_options(mytarget PRIVATE
"$<$<CONFIG:Release>: $<$<CXX_COMPILER_ID:MSVC>:/GS>>
$<$<CONFIG:RelWithDebInfo>:$<$<CXX_COMPILER_ID:MSVC>:/GS>>")
Now I also want to let the user configure this, and I've added an option:
option(MYTARGET_ENABLE_GS "Enable /GS" OFF)
So now, I (obviously) want to enable the /GS flag if the user enabled this option, and if they did, I want to add it if the compiler is MSVC, and it should be added to the Release and RelWithDebInfo configurations.
This is pretty nested, and I can't seem to get it right. This is as far as I got:
target_compile_options(mytarget PRIVATE
"$<$<BOOL:MYTARGET_ENABLE_GS>:
$<$<CONFIG:Release>: $<$<CXX_COMPILER_ID:MSVC>:/GS>>
$<$<CONFIG:RelWithDebInfo>:$<$<CXX_COMPILER_ID:MSVC>:/GS>>>")
Edit: Fixed, see below.
I've had to use the $<$<BOOL:...>> because that "translates" the option (which can be on/off or true/false, to 0 or 1, which the generator expression needs.
However above line doesn't work: It doesn't add (or not add) /GS.
I'd like to know:
1) Where is my mistake? How to do this? And
Stuff like this results in pretty convoluted nested expressions, that are really hard to read - imagine 6 months down the line reading that line of code again, even if it is documented. And it's so easy to misplace a > or something like that.
I could probably use "manual" ifs to make this more readable, but imagine having 5-10 of such options - writing an if/end with a target_compile_options inside results in like 15-30 lines of if/end code, which is also not very pretty to look at. What's the best way to do this?
Edit: I was nearly there. Variables have to be enclosed with ${...} in generator expressions. So it's for example:
target_compile_options(mytarget PRIVATE
"$<$<BOOL:${MYTARGET_ENABLE_GS}>:
$<$<CONFIG:Release>: $<$<CXX_COMPILER_ID:MSVC>:/GS>>
$<$<CONFIG:RelWithDebInfo>:$<$<CXX_COMPILER_ID:MSVC>:/GS>>>")
and that works great.
Which still leaves point "2)", which I would be keen to getting insights on.
When you generate a MSVC solution, the build type (Release, Debug, etc.) is unknown until you actually run the build. Thus, using generator expression for that is correct.
But for the 2 other variables (does user set MYTARGET_ENABLE_GS to OFF and is generation performed for MSVC), they are resolved at configuration time. So, you don't have to check them in a generator expression. You could simply write:
if(MSVC AND MYTARGET_ENABLE_GS)
target_compile_options(mytarget PRIVATE "$<$<OR:$<CONFIG:Release>,$<CONFIG:RelWithDebInfo>>:/GS>")
endif()
This solution also uses $<OR:?[,?]...> generator expression to regroup under the same expression both cases you build in Release OR RelWithDebInfo
Whenever you may use if command, use it. Generator expressions are not replacement for if command.
Generator expressions allow to use conditions dependent on build type. Because on multi-configuration build systems, like Visual Studio, build type isn't known at configuration stage, you cannot use such condition in if command.
But generator expressions are ugly, so do not use them when it is not needed.
There is nothing bad in
if(MYTARGET_ENABLE_GS)
target_compile_options(mytarget PRIVATE "$<$<CONFIG:Release>:$<$<CXX_COMPILER_ID:MSVC>:/GS>>$<$<CONFIG:RelWithDebInfo>:$<$<CXX_COMPILER_ID:MSVC>:/GS>>")
endif()
If you want to check an option at the beginning, but create a target later, you may store generator expression in the variable, and use this variable later:
set(additional_options)
# Depending on parameters, add options to 'additional_options' list.
if(MYTARGET_ENABLE_GS)
list(APPEND additional_options "$<$<CONFIG:Release>:$<$<CXX_COMPILER_ID:MSVC>:/GS>>$<$<CONFIG:RelWithDebInfo>:$<$<CXX_COMPILER_ID:MSVC>:/GS>>")
endif()
if(<other option>)
list(APPEND additional_options <...>)
endif()
# ...
target_compile_options(mytarget PRIVATE ${additional_options})
CMake's documentation a generator expressions works if your config matches any configuration listed after CONFIG:, but I couldn't find the syntax documented anywhere. Trial and error show the following works correctly:
if(MSVC AND MYTARGET_ENABLE_GS)
target_compile_options(mytarget PRIVATE "$<$<CONFIG:Release,RelWithDebInfo>:/GS>")
endif()
Sadly, CMake follows the awkward "implicit lib" convention, which inevitably causes problems when library names don't actually follow the convention (e.g. zlib), or have 'lib' as an explicit part of their name.
For example, suppose I want to add libusb:
add_library(libusb ...)
On Windows this will correctly produce libusb.lib. On Unix it will produce the hilarious liblibusb.a. Is there any way to prevent this behaviour? I know I can set the output name explicitly using OUTPUT_NAME but I'd have to use some funky generator expressions to preserve libusb.lib on Windows. I wonder if there is a better way?
(And no add_library(usb ... is not a solution; the library is called libusb not usb.)
You can modify it via CMAKE_STATIC_LIBRARY_PREFIX. So in your case just do after your project() command:
set(CMAKE_STATIC_LIBRARY_PREFIX "")
Or you can change it per target via the PREFIX target property.
I would like to set up a cmake script with some options (flags and strings). For some of the options I would like to use environment variables as a default. Basically, I'm trying to emulate something like MY_OPTION ?= default in a Makefile. I tried the following:
project (Optiontest)
option(MY_OPTION
"Documentation"
$ENV{MY_OPTION}
FORCE)
message("value: ${MY_OPTION}")
I called this in the following way:
$ cmake -DMY_OPTION=ON .
value: ON
$ cmake -DMY_OPTION=OFF .
value: OFF
$ MY_OPTION=OFF cmake .
value: OFF
$ MY_OPTION=ON cmake .
value: OFF
My problem is that the last line should be ON as well.
For bonus karma: I would actually prefer three levels of preference. The value of -DMY_OPTION should be used if given. If not, the value of a set environment variable MY_OPTION should be used. If this is also not set, a constant should be used. I guess, I could use a bunch of nested if statements and somehow check if the variables are set, but I don't know how and I hope there is a better way.
FORCE is (as of CMake 3.0.2) not a valid parameter for option.
This is the primary source of problems. CMake will interpret the string FORCE as the desired initial value of the option in absence of an environment variable. The usual contrived rules for string-to-truth-value-conversion apply, resulting in the option being set to OFF by this call.
Second, you need to account for the fact that the environment variable is not set. Your current code misses to handle that case properly. $ENV{MY_OPTION} will evaluate to the empty string in that case. If you evaluate the set values in both the cache and the environment, you can enforce any behavior that you want.
In general, you should think about what you actually want here. Usually, FORCE setting a cached variable is a bad idea and I would not be surprised if you found your initial argument for doing this flawed after some careful reevaluation.
Maybe value of MY_OPTION cached in CMake cache? Do you try to clean cmake cache after third call MY_OPTION=OFF cmake .?
I have code that looks like the following (below) where ${IMPJAVASRC:T} evaluates to PJCentric.java. I would like to compare this string variable to a prefix consisting of just the characters "PJC" since there are other modules with the same prefix which I would like to compile with a different -classpath than other modules that start with a different prefix. However, my statement below does not evaluate to true. Any suggestions?
.if !empty(${IMPJAVASRC:T}:MPJC*)
(compile one way)
.else
(compile another way)
You probably can do this if you use specifically GNU Make e.g. with its conditional functions or its control functions. But other make programs don't give you this ability. However, there also exist better building programs than make such as omake and Java have also ant
The Story So Far
I've got a nice solution with a desktop application project, a few library projects, and a couple of development tools projects (also desktop applications). At the moment, my build server outputs all of the code into one OutputPath. So we end up with
drop-x.y.z\
Company.MainApplication.exe <-- main application
Company.MainApplicationCore.dll <-- libraries
Helper.exe <-- developer tools
Grapher.exe
Parser.exe
... <-- the rest of the output
But, we're growing up and people outside of our team want access to our tools. So I want to organize the output. I decided that what we would want is a different OutputPath per executable project
drop-x.y.z\
Company.MainApplication\
Company.MainApplication.exe <-- main application
Company.MainApplicationCore.dll <-- libraries
... <-- application specific output
Helper\
Helper.exe <-- developer tools
... <-- tool specific output
Grapher\
Grapher.exe
...
Parser\
Parser.exe
...
What I Did
I found this simple command. I like it because it retains all the Solution working-dir context that makes msbuild a pain.
msbuild /target:<ProjectName>
For example, from my solution root as a working directory, I would call
PS> msbuild /target:Helper /property:OutputPath="$pwd\out\Helper"
I'm testing this from PowerShell, so that $pwd resolves to the full path to my working directory, or the Solution root in this case. I get the output I desire.
However, when I run this command
PS> msbuild /target:Company.MainApplication /property:OutputPath="$pwd\out\Company.MainApplication"
I get the following error output (there's no more information, I ran with /verbosity:diagnostic)
The target "Company.MainApplication" does not exist in the project.
What I Need
The command fails on any project with a dot or dots in the name. I tried with many combinations of working directories and properties. I tried several ways of escaping the property values. I also tried running the command from a <Task> in a targets file.
I need to know either
A) How to fix this command to work property
B) How to achieve the same output with minimal friction
Try using an underscore as an escape character for the dot in the target parameter, e.g.
msbuild /target:Company_MainApplication /property:OutputPath="$pwd\out\Company.MainApplication"
Specify the target after the -target: switch in the format :. If the project name contains any of the characters %, $, #, ;, ., (, ), or ', replace them with an _ in the specified target name.
https://learn.microsoft.com/en-us/visualstudio/msbuild/how-to-build-specific-targets-in-solutions-by-using-msbuild-exe?view=vs-2019
Dan Nolan's answer and comments are correct. Just want to supplement the Microsoft documentation.
The /targets: switch is to identify a <Target to run in the project file. You need to supply your .csproj file as a an argument that is not prefixed by a /xx option marker.
You might also want to work based on the .sln file. In that case, you still dont specify the project in the .sln to build in this manner. I'll leave you to search up the correct syntax in case that's what you end up doing.