Is there a way to set a variable in a CMake script to the output of a shell command?
Something like SET(FOO COMMAND "echo bar") would come to mind
You want the execute_process command.
In your case, on Windows:
execute_process(COMMAND CMD /c echo bar OUTPUT_VARIABLE FOO)
or on Linux, simply:
execute_process(COMMAND echo bar OUTPUT_VARIABLE FOO)
In this particular case, CMake offers a cross-platform solution. CMake can itself be used to run commands that can be used on all systems, one of which is echo. To do this, CMake should be passed the command line arg -E. For the full list of such commands, run cmake -E help
Inside a CMake script, the CMake executable is referred to by ${CMAKE_COMMAND}, so the script needs to do:
execute_process(COMMAND ${CMAKE_COMMAND} -E echo bar OUTPUT_VARIABLE FOO)
Related
I have the following CMake snippet that runs COMMAND in WORKING_DIRECTORY. I tried different ways to pass the environment variable (MBEDTLS_INCLUDE_DIR=${CMAKE_CURRENT_SOURCE_DIR}/../mbedtls/mbedtls/include) but without success.
The snippet that works (without env variable):
set(BUILD_CMD cargo build --features parsec-client/no-fs-permission-check)
set(WORKING_DIR "${CMAKE_CURRENT_SOURCE_DIR}/parsec_se_driver")
execute_process( COMMAND ${BUILD_CMD}
RESULT_VARIABLE CMD_ERROR
WORKING_DIRECTORY ${WORKING_DIR} )
if(NOT ${CMD_ERROR} MATCHES "0")
MESSAGE(SEND_ERROR "BUILD_CMD STATUS:" ${CMD_ERROR})
endif()
How can I pass the env variable to the execute_process?
If I write something like this:
execute_process( COMMAND MBEDTLS_INCLUDE_DIR=${CMAKE_CURRENT_SOURCE_DIR}/../mbedtls/mbedtls/include cargo build --features parsec-client/no-fs-permission-check
RESULT_VARIABLE CMD_ERROR
WORKING_DIRECTORY ${WORKING_DIR} )
or taking different parts to variables, or adding quotes, I get:
BUILD_CMD STATUS:No such file or directory
As recommended in the CMake mailing list here, your solution using set(ENV ...) is perfectly valid:
set(ENV{MBEDTLS_INCLUDE_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/../mbedtls/mbedtls/include)
execute_process(
COMMAND ${BUILD_CMD}
RESULT_VARIABLE CMD_ERROR
WORKING_DIRECTORY ${WORKING_DIR}
)
You could also use CMake's command line utility to run the command in a modified environment using cmake -E env:
execute_process(
COMMAND ${CMAKE_COMMAND} -E env
MBEDTLS_INCLUDE_DIR="${CMAKE_CURRENT_SOURCE_DIR}/../mbedtls/mbedtls/include" ${BUILD_CMD}
RESULT_VARIABLE CMD_ERROR
WORKING_DIRECTORY ${WORKING_DIR}
)
Suppose I have a custom target in CMake for unit tests like the below
add_custom_target(
test
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/ATest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/BTest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/CTest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/DTest)
but I want to add an additional test to the target based on whether an external dependency is found. Currently, I did it with
if(EXTERNAL_FOUND)
add_custom_target(
test
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/ATest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/BTest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/CTest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/DTest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/ETest)
else()
add_custom_target(
test
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/ATest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/BTest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/CTest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/DTest)
endif()
This is not very elegant and it quickly becomes unmanageable when there are multiple conditions. Is there something like append to custom target so we can write the below instead?
add_custom_target(
test
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/ATest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/BTest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/CTest
COMMAND ${CMAKE_CURRENT_BINARY_DIR}/DTest)
if(EXTERNAL_FOUND)
# I can't seem to find something like this
append_custom_target(test COMMAND ${CMAKE_CURRENT_BINARY_DIR}/ETest)
else()
Or is there a better way to do this?
You can use add_custom_command and use it as dependency to your target. With the custom command you can APPEND commands with same OUTPUT:
add_custom_target(
test
DEPENDS test-cmd
)
add_custom_command(
OUTPUT test-cmd
COMMAND ${CMAKE_COMMAND} -E echo "ATest"
COMMAND ${CMAKE_COMMAND} -E echo "BTest"
COMMAND ${CMAKE_COMMAND} -E echo "CTest"
COMMAND ${CMAKE_COMMAND} -E echo "DTest"
)
if(EXTERNAL_FOUND)
add_custom_command(
OUTPUT test-cmd APPEND
COMMAND ${CMAKE_COMMAND} -E echo "ETest"
)
endif()
# test-cmd is not actually generated so set it to symbolic
set_source_files_properties(test-cmd PROPERTIES SYMBOLIC "true")
See SYMBOLIC for the artifical source file property.
In my Cmake script I need to redirect the standard output to the NUL / /dev/null device. I searched the CMake documentation for a portable solution but didn't find something.
I could do something like
if (WIN32)
set(NULDEV NUL)
else()
set(NULDEV /dev/null)
endif()
and use in the code ${NULDEV}, but I'd prefer a portable solution coming with CMake.
Edit usage form:
add_custom_target(docs
COMMENT "Generating documentation."
COMMAND ${CMAKE_COMMAND} -E chdir ${PROJECT_BINARY_DIR} "${THE_PROGRAM}" arguments > nul
)
Is this possible?
If you are running a shell command using execute_process() and want to quite the output. you can use the OUTPUT_QUIET and/or ERROR_QUIET options.
From the execute_process documentation:
OUTPUT_QUIET, ERROR_QUIET
The standard output or standard error results will be quietly ignored.
Example 1:
execute_process(COMMAND "${THE_PROGRAM}" argument OUTPUT_QUIET)
If you are using add_custom_target(), then it is unfortunately not that straight forward. What you could do is:
Example 2:
Create a wrapper cmake script for executing your program:
# generate_docs.cmake
execute_process(COMMAND "${THE_PROGRAM}" argument OUTPUT_QUIET)
Let CMake execute the wrapper script instead of running the program directly:
add_custom_target(docs
COMMENT "Generating documentation."
COMMAND ${CMAKE_COMMAND} -P generate_docs.cmake
)
I have a console application called "foo", which takes a reference text file as input (in.txt) and generates text at standard output (I want to keep this behaviour).
In make (not cmake), I use a test target, which calls foo and redirects the output to a file (out.txt) as follows. Then, I use diff to compare the file out.txt with the expected refernece (ref.txt)
test:
./foo -a test/in.txt > test/out.txt
diff test/out.txt test/ref.txt
This works fine using make. Now my question is; how can I use cmake to create a similar Makefile?
From within a subdrectory called build, I tried
project(foo)
...
add_test(NAME test1 COMMAND ./foo ../test/in.txt > ../test/out.txt)
enable_testing()
Using cmake version 3.5, I get a Makefile without errors, but when I call make test, the test itself fails. It seems the cmake command add_test supports command line arguments, but not the redirection. I tried quotes and escaping witout success. Since I could not pass this part, I didn't try to use diff. I just imagine that I could pack foo and diff in one line using & as you can do with bash. That would be the second step.
Turning my comment into an answer
As #Tsyvarev has stated, CTest commands are not run in a shell's context. But you could just add the shell needed yourself and use e.g. sh as the command to be called with add_test().
I've run some tests with your example code and the following did work successfully:
add_test(NAME test1 COMMAND sh -c "$<TARGET_FILE:foo> ../test/in.txt > ../test/out.txt")
This solution is not platform independent (it depends on sh to be available in the search paths).
So if you want to be more flexible you could do something like:
include(FindUnixCommands)
file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/test/in.txt" _in)
file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/test/out.txt" _out)
if (BASH)
add_test(
NAME test1
COMMAND ${BASH} -c "$<TARGET_FILE:foo> ${_in} > ${_out}"
)
else()
if (WIN32)
add_test(
NAME test1
COMMAND ${CMAKE_COMMAND} -E chdir $<TARGET_FILE_DIR:foo> $ENV{ComSpec} /c "$<TARGET_FILE_NAME:foo> ${_in} > ${_out}"
)
else()
message(FATAL_ERROR "Unknown shell command for ${CMAKE_HOST_SYSTEM_NAME}")
endif()
endif()
Additionally there is the possibility to execute a more platform independent diff with ${CMAKE_COMMAND} -E compare_files <file1> <file2>. So you could simplify your complete makefile based example in CMake with:
add_custom_command(
TARGET foo
POST_BUILD
COMMAND ${CMAKE_COMMAND} -E echo "Running $<TARGET_FILE_NAME:foo> ..."
COMMAND foo in.txt > out.txt
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test
)
add_test(
NAME test1
COMMAND ${CMAKE_COMMAND} -E compare_files in.txt out.txt
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test
)
References
Integrate bash test scripts in cmake
CMake: piping commands to executable
cmake: make tests successfully passing part of the build process
They say you cannot:
There is no redirection of output using add_test arguments.
Unlike to commands in add_custom_command, which are executed as a part of makefile receipts (that is, in the context of some shell), tests are executed directly by CTest, without any shell involved. So, shell mechanisms don't work for tests.
You may create wrapper script, which calls program, given as parameter, and performs redirection, futher diff and so on. Then use this script (with appropriate arguments) as a COMMAND for add_test.
I have a console application called "foo", which takes a reference text file as input (in.txt) and generates text at standard output (I want to keep this behaviour).
In make (not cmake), I use a test target, which calls foo and redirects the output to a file (out.txt) as follows. Then, I use diff to compare the file out.txt with the expected refernece (ref.txt)
test:
./foo -a test/in.txt > test/out.txt
diff test/out.txt test/ref.txt
This works fine using make. Now my question is; how can I use cmake to create a similar Makefile?
From within a subdrectory called build, I tried
project(foo)
...
add_test(NAME test1 COMMAND ./foo ../test/in.txt > ../test/out.txt)
enable_testing()
Using cmake version 3.5, I get a Makefile without errors, but when I call make test, the test itself fails. It seems the cmake command add_test supports command line arguments, but not the redirection. I tried quotes and escaping witout success. Since I could not pass this part, I didn't try to use diff. I just imagine that I could pack foo and diff in one line using & as you can do with bash. That would be the second step.
Turning my comment into an answer
As #Tsyvarev has stated, CTest commands are not run in a shell's context. But you could just add the shell needed yourself and use e.g. sh as the command to be called with add_test().
I've run some tests with your example code and the following did work successfully:
add_test(NAME test1 COMMAND sh -c "$<TARGET_FILE:foo> ../test/in.txt > ../test/out.txt")
This solution is not platform independent (it depends on sh to be available in the search paths).
So if you want to be more flexible you could do something like:
include(FindUnixCommands)
file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/test/in.txt" _in)
file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/test/out.txt" _out)
if (BASH)
add_test(
NAME test1
COMMAND ${BASH} -c "$<TARGET_FILE:foo> ${_in} > ${_out}"
)
else()
if (WIN32)
add_test(
NAME test1
COMMAND ${CMAKE_COMMAND} -E chdir $<TARGET_FILE_DIR:foo> $ENV{ComSpec} /c "$<TARGET_FILE_NAME:foo> ${_in} > ${_out}"
)
else()
message(FATAL_ERROR "Unknown shell command for ${CMAKE_HOST_SYSTEM_NAME}")
endif()
endif()
Additionally there is the possibility to execute a more platform independent diff with ${CMAKE_COMMAND} -E compare_files <file1> <file2>. So you could simplify your complete makefile based example in CMake with:
add_custom_command(
TARGET foo
POST_BUILD
COMMAND ${CMAKE_COMMAND} -E echo "Running $<TARGET_FILE_NAME:foo> ..."
COMMAND foo in.txt > out.txt
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test
)
add_test(
NAME test1
COMMAND ${CMAKE_COMMAND} -E compare_files in.txt out.txt
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test
)
References
Integrate bash test scripts in cmake
CMake: piping commands to executable
cmake: make tests successfully passing part of the build process
They say you cannot:
There is no redirection of output using add_test arguments.
Unlike to commands in add_custom_command, which are executed as a part of makefile receipts (that is, in the context of some shell), tests are executed directly by CTest, without any shell involved. So, shell mechanisms don't work for tests.
You may create wrapper script, which calls program, given as parameter, and performs redirection, futher diff and so on. Then use this script (with appropriate arguments) as a COMMAND for add_test.