# Just can't get the location of the project's source tree to CPack.
**URL:** https://discourse.cmake.org/t/just-cant-get-the-location-of-the-projects-source-tree-to-cpack/6396
**Category:** Code
**Tags:** os:windows, cpack:nsis
**Created:** [September 3, 2022, 6:39am UTC](https://discourse.cmake.org/t/just-cant-get-the-location-of-the-projects-source-tree-to-cpack/6396 "2022-09-03T06:39:29Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Lord-Kamina](https://discourse.cmake.org/u/Lord-Kamina)
#### Post date: [September 3, 2022, 6:39am UTC](https://discourse.cmake.org/t/just-cant-get-the-location-of-the-projects-source-tree-to-cpack/6396/1 "2022-09-03T06:39:29Z")
I’m trying to create an nsis installer via the GH Actions runners.
I’ve defined some code in the INSTALL section, to copy and bundle all the libs (I’m using a shell script , rather than the built-in functionality).
The problem is, I just can’t get the install script to know where the source tree is located at.
Of course, my first instinct was to just use `CMAKE_SOURCE_DIR`, when that didn’t work, I tried other versions (such as `PROJECT_SOUR_DIR` and `_SOURCE_DIR`), none of which work.
Then I realized CPACK should be able to get variables that start with `CPACK`, so I made a `CPACK_TOP_SOURCE_DIR` which is set the `CMAKE_SOURCE_DIR`; again, didn’t work. I reasoned maybe it’s because it was being re-set on every run (including CPack) and thus was being set to empty during install. So, I came up with the following:
```cmake
if (CMAKE_SOURCE_DIR AND (NOT (CMAKE_SOURCE_DIR STREQUAL CPACK_TOP_SOURCE_DIR)))
set (CPACK_TOP_SOURCE_DIR "${CMAKE_SOURCE_DIR}" CACHE INTERNAL "Source directory to be used by CPack." FORCE)
endif()
```
Looking into CPackConfig.txt shows that it apparently works:
```bash
runneradmin@fv-az250-215 MINGW64 /d/a/performous/performous/performous/build
# cat CPackConfig.cmake | grep TOP_SOURCE
set(CPACK_TOP_SOURCE_DIR "D:/a/performous/performous/performous")
```
But again, this doesn’t work during the install phase.
```cmake
install(CODE [[
message ("SOURCE DIR IS: ${CPACK_TOP_SOURCE_DIR}")
]])
```
prints
```bash
CPack: Install projects
CPack: - Run preinstall target for: Performous
CPack: - Install project: Performous []
SOURCE DIR IS:
```
What am I doing wrong, and how can I fix it? At this point, the only idea I’m getting is to maybe use a file instead of a variable, and then read the contents of the file, but that’s an even nastier hack that what I’m already using…
---
### Author:  [@mhebes](https://discourse.cmake.org/u/mhebes)
#### Post date: [September 20, 2022, 12:16am UTC](https://discourse.cmake.org/t/just-cant-get-the-location-of-the-projects-source-tree-to-cpack/6396/2 "2022-09-20T00:16:12Z")
Could you explain why you need the source directory in the install script in the first place? Just in case there’s a more elegant solution
---
### Author:  [@Lord-Kamina](https://discourse.cmake.org/u/Lord-Kamina)
#### Post date: [September 20, 2022, 2:55am UTC](https://discourse.cmake.org/t/just-cant-get-the-location-of-the-projects-source-tree-to-cpack/6396/3 "2022-09-20T02:55:52Z")
I’m running a script to gather and copy runtime dependencies (that does a better job than the built-in functionality) and I needed the source to pass folders and options properly to it.
I managed to solve it in a very hacky but functional way. I first check if CMAKE\_SOURCE\_DIR is set; if it is, I write its value to a temp file, which I then read during the install phase. It’s dirty but it works.
---
### Author:  [@mhebes](https://discourse.cmake.org/u/mhebes)
#### Post date: [September 20, 2022, 11:33am UTC](https://discourse.cmake.org/t/just-cant-get-the-location-of-the-projects-source-tree-to-cpack/6396/4 "2022-09-20T11:33:27Z")
Gotcha. “Whatever works” is usually the only sensible option with CMake 🙂 . If you do ever want to revisit it though:
CPack _does_ have your variable as you saw. If you were to e.g. make a custom NSIS project file template, you’d have access to that variable inside that template.
`cmake_install.txt`, which is run by CPack in order to build an installation folder it can compress, and is the thing with your `message(` call in it, does not have access to the variable.
The problem is that `cmake_install.cmake` is what runs the `install(CODE`, and it’s invoked as a separate script with something like `cmake -P cmake_install.cmake`, so it gets none of your variables.
So `cmake_install.cmake` has the `message("SOURCE DIR IS: ${CPACK_TOP_SOURCE_DIR}"` but that var is never set in the context of the install script. You can move the variable into the installation like this:
```auto
install(CODE "set(CPACK_TOP_SOURCE_DIR ${CPACK_TOP_SOURCE_DIR})")
install(CODE [[
message("Source dir = ${CPACK_TOP_SOURCE_DIR}")
]])
```
And then if you re-run `cmake` and either `cmake --install . --prefix .` or `cpack` you’ll find your message correctly printed. You’ll find both the `set(` and `message(` lines inside the `cmake_install.cmake`.