# How to force a static archive to be recreated when another file changes

**URL:** https://discourse.cmake.org/t/how-to-force-a-static-archive-to-be-recreated-when-another-file-changes/15240
**Category:** Usage
**Created:** [October 14, 2025, 2:05pm UTC](https://discourse.cmake.org/t/how-to-force-a-static-archive-to-be-recreated-when-another-file-changes/15240 "2025-10-14T14:05:55Z")
**Posts on this page:** 6
**Page:** 1

<div class="post-metadata">

### Author: ![alcroito](https://discourse.cmake.org/user_avatar/discourse.cmake.org/alcroito/32/186_2.png) [@alcroito](https://discourse.cmake.org/u/alcroito)
#### Post date: [October 14, 2025, 2:05pm UTC](https://discourse.cmake.org/t/how-to-force-a-static-archive-to-be-recreated-when-another-file-changes/15240/1 "2025-10-14T14:05:55Z")

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I have the following sample project illustrating the issue:

```auto
cmake_minimum_required(VERSION 3.16)
project(proj LANGUAGES CXX)

# Allow using response files.
if(APPLE)
    set(CMAKE_CXX_ARCHIVE_CREATE "libtool -o <TARGET> <LINK_FLAGS> <OBJECTS>")
endif()

set(cpp_file "${CMAKE_CURRENT_BINARY_DIR}/core.cpp")
file(WRITE "${cpp_file}" "int core() { return 1;}")

set(response_file "${CMAKE_CURRENT_BINARY_DIR}/response_file.rsp")
file(WRITE "${response_file}" "-v")

add_library(foo STATIC "${cpp_file}")
target_sources(foo PRIVATE "${response_file}")
set_target_properties(foo PROPERTIES STATIC_LIBRARY_OPTIONS "@${response_file}")

# Make foo archiving rerun if the response file changes.
# Doesn't work for static libraries, only works for shared library targets.
set_target_properties(foo PROPERTIES LINK_DEPENDS "${response_file}")

```

I have a static library `foo` built by cmake, which is supposed to additionally apply the options from an external response file. The response file is generated outside of CMake.  
I add the response file to `STATIC_LIBRARY_OPTIONS` of the target.

With the current project, if i `touch` the response file, `foo` is not rebuilt.

If `foo` were a shared library, I could use the `LINK_DEPENDS` property to achieve my goal.

Is there a way to model this in CMake with static libraries?

Note I would like a solution that works for any arbitrary file as a dependency (e.g. a timestamp file), not necessarily something that appears on the command line of the archiver invocation or in ``STATIC_LIBRARY_OPTIONS``.

Thanks!

The best I could come up with so far is to create an object library with an empty source file, add the response file to its `OBJECT_DEPENDS` property, and then link the object library into the static library.

```auto
set(object_file "${CMAKE_CURRENT_BINARY_DIR}/object.cpp")
file(WRITE "${object_file}" "")
add_library(obj OBJECT "${object_file}")
set_property(SOURCE "${object_file}" PROPERTY OBJECT_DEPENDS "${response_file}")

target_link_libraries(foo PRIVATE $<LINK_ONLY:obj>)

```

This achieves the rebuilding part, but is suboptimal due to extra needless compilation.

---

<div class="post-metadata">

### Author: ![vito.gamberini](https://discourse.cmake.org/user_avatar/discourse.cmake.org/vito.gamberini/32/4376_2.png) [@vito.gamberini](https://discourse.cmake.org/u/vito.gamberini)
#### Post date: [October 15, 2025, 11:26am UTC](https://discourse.cmake.org/t/how-to-force-a-static-archive-to-be-recreated-when-another-file-changes/15240/2 "2025-10-15T11:26:19Z")

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Add the response file as a source for the target you would like to be rebuilt when the response file changes

---

<div class="post-metadata">

### Author: ![alcroito](https://discourse.cmake.org/user_avatar/discourse.cmake.org/alcroito/32/186_2.png) [@alcroito](https://discourse.cmake.org/u/alcroito)
#### Post date: [October 15, 2025, 11:42am UTC](https://discourse.cmake.org/t/how-to-force-a-static-archive-to-be-recreated-when-another-file-changes/15240/3 "2025-10-15T11:42:01Z")

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I tried that, it doesn’t work.

See the code above, it has.

```auto
target_sources(foo PRIVATE "${response_file}")

```

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<div class="post-metadata">

### Author: ![craig.scott](https://discourse.cmake.org/user_avatar/discourse.cmake.org/craig.scott/32/20_2.png) [@craig.scott](https://discourse.cmake.org/u/craig.scott)
#### Post date: [October 20, 2025, 4:04am UTC](https://discourse.cmake.org/t/how-to-force-a-static-archive-to-be-recreated-when-another-file-changes/15240/4 "2025-10-20T04:04:03Z")

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I wonder if that approach not working is related to the behavior of having the [`OPTIMIZE_DEPENDENCIES`](https://cmake.org/cmake/help/latest/prop_tgt/OPTIMIZE_DEPENDENCIES.html) target property set to true? Maybe worth checking if you have that enabled and see if disabling it makes any difference.

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<div class="post-metadata">

### Author: ![alcroito](https://discourse.cmake.org/user_avatar/discourse.cmake.org/alcroito/32/186_2.png) [@alcroito](https://discourse.cmake.org/u/alcroito)
#### Post date: [October 20, 2025, 8:29am UTC](https://discourse.cmake.org/t/how-to-force-a-static-archive-to-be-recreated-when-another-file-changes/15240/5 "2025-10-20T08:29:22Z")

</div>

Thanks for the hint, but it doesn’t make a difference. Neither setting it to ON/OFF nor undefined.

Given the documentation for OPTIMIZE\_DEPENDENCIES, I thought maybe i can force a file-level dependency by adding a custom\_command indirection, but that didn’t help either.

This was my attempt:

```auto
cmake_minimum_required(VERSION 3.16)
project(proj LANGUAGES CXX)

# Allow using response files.
if(APPLE)
    set(CMAKE_CXX_ARCHIVE_CREATE "libtool -o <TARGET> <LINK_FLAGS> <OBJECTS>")
endif()

set(cpp_file "${CMAKE_CURRENT_BINARY_DIR}/core.cpp")
file(CONFIGURE OUTPUT "${cpp_file}" CONTENT "int core() { return 1;}")

set(response_file "${CMAKE_CURRENT_BINARY_DIR}/response_file.rsp")
set(response_file_fake "${CMAKE_CURRENT_BINARY_DIR}/response_file_fake.txt")
file(CONFIGURE OUTPUT "${response_file}" CONTENT "-v")

add_custom_command(
    OUTPUT "${response_file_fake}"
    COMMAND ${CMAKE_COMMAND} -E touch "${response_file_fake}"
    DEPENDS "${response_file}"
)

add_library(foo STATIC "${cpp_file}")
target_sources(foo PRIVATE "${response_file_fake}" "${response_file}")
set_target_properties(foo PROPERTIES STATIC_LIBRARY_OPTIONS "@${response_file}")

```

touching the response file still doesn’t force archive recreation, even though the custom\_command rule is triggered.

---

<div class="post-metadata">

### Author: ![craig.scott](https://discourse.cmake.org/user_avatar/discourse.cmake.org/craig.scott/32/20_2.png) [@craig.scott](https://discourse.cmake.org/u/craig.scott)
#### Post date: [October 20, 2025, 8:14pm UTC](https://discourse.cmake.org/t/how-to-force-a-static-archive-to-be-recreated-when-another-file-changes/15240/6 "2025-10-20T20:14:03Z")

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The response file is only used at the linking step, so I’m wondering if adding it as a source file is the wrong place for it. The `LINK_DEPENDS` target property seems conceptually like the place the response file should be added, but I don’t know off hand if it is used for the static archiver. If this was a shared library, that would seem the right property to add it to. EDIT: I just saw you already mentioned this in your original post. Potentially we need a `STATIC_LINK_DEPENDS` property to more easily achieve what you’re trying to do.