# add\_custom\_target dependencies
**URL:** https://discourse.cmake.org/t/add-custom-target-dependencies/3342
**Category:** Usage
**Created:** [May 17, 2021, 9:43am UTC](https://discourse.cmake.org/t/add-custom-target-dependencies/3342 "2021-05-17T09:43:36Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@kmosk](https://discourse.cmake.org/u/kmosk)
#### Post date: [May 17, 2021, 9:43am UTC](https://discourse.cmake.org/t/add-custom-target-dependencies/3342/1 "2021-05-17T09:43:36Z")
my CMakeLists.txt:
```cmake
# wxFormBuilder generation
set(FORM_BUILDER_PROJECT ${PROJECT_SOURCE_DIR}/source/view/gen.fbp)
set(GENERATED_VIEW_DIR ${PROJECT_SOURCE_DIR}/source/view/generated)
set(GENERATED_VIEW_FILE_CPP ${GENERATED_VIEW_DIR}/gen_view.cpp)
set(GENERATED_VIEW_FILE_H ${GENERATED_VIEW_DIR}/gen_view.h)
set(GENERATED_VIEW_FILES
${GENERATED_VIEW_FILE_CPP}
${GENERATED_VIEW_FILE_H}
${GENERATED_VIEW_DIR}/info.png.h
${GENERATED_VIEW_DIR}/logo.png.h)
set(GENERATED_FILES_FIX_SCRIPT
${PROJECT_SOURCE_DIR}/cmake/script/wx_string_to_cpp_define.cmake)
add_custom_target(gen_view
COMMAND ${CMAKE_COMMAND} -E make_directory ${GENERATED_VIEW_DIR}
COMMAND ${FORMBUILDER_EXE} -g ${FORM_BUILDER_PROJECT}
COMMAND ${CMAKE_COMMAND} -D filename="${GENERATED_VIEW_FILE_H}" -P ${GENERATED_FILES_FIX_SCRIPT}
COMMAND ${CMAKE_COMMAND} -D filename="${GENERATED_VIEW_FILE_CPP}" -P ${GENERATED_FILES_FIX_SCRIPT}
DEPENDS ${FORM_BUILDER_PROJECT}
BYPRODUCTS ${GENERATED_VIEW_FILES}
WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
COMMENT "Generating view files from wxformbuilder project"
SOURCES ${FORM_BUILDER_PROJECT})
add_executable(my_exe WIN32)
...
target_sources(my_exe PRIVATE
source/main.cpp
${GENERATED_VIEW_FILE_CPP}
...
)
```
When I execute `cmake --build cmake-build / --target my_exe` for the first time, the `gen_view` target is built. This is logical. But when I run the same command again, the build of the `gen_view` target starts again, even though I haven’t changed anything and the generated files don’t change either. How to make it so that the `gen_view` assembly is only when `GENERATED_VIEW_FILES` or `FORM_BUILDER_PROJECT` are somehow changed?
---
### Author:  [@marc.chevrier](https://discourse.cmake.org/u/marc.chevrier)
#### Post date: [May 17, 2021, 1:41pm UTC](https://discourse.cmake.org/t/add-custom-target-dependencies/3342/2 "2021-05-17T13:41:36Z")
This is the expected behavior. As specified in the [documentation](https://cmake.org/cmake/help/latest/command/add_custom_target.html):
> The target has no output file and is _always considered out of date_.
> Use the [`add_custom_command()`](https://cmake.org/cmake/help/git-master/command/add_custom_command.html#command:add_custom_command) command to generate a file with dependencies.
---
### Author:  [@kmosk](https://discourse.cmake.org/u/kmosk)
#### Post date: [May 17, 2021, 2:12pm UTC](https://discourse.cmake.org/t/add-custom-target-dependencies/3342/3 "2021-05-17T14:12:08Z")
Thnx, is it possible to add the cmake function I wrote to custom\_command?
---
### Author:  [@marc.chevrier](https://discourse.cmake.org/u/marc.chevrier)
#### Post date: [May 17, 2021, 2:56pm UTC](https://discourse.cmake.org/t/add-custom-target-dependencies/3342/4 "2021-05-17T14:56:18Z")
Yes, [`add_custom_command()`](https://cmake.org/cmake/help/git-master/command/add_custom_command.html#command:add_custom_command) supports `COMMAND` option in the same way as [`add_custom_target()`](https://cmake.org/cmake/help/git-master/command/add_custom_command.html#command:add_custom_target).
Have a look also at options `DEPENDS` and `DEPFILE`.