cmake: Pass installed include dir to mpgen #375

pull VijayabaskarR-06 wants to merge 1 commits into bitcoin-core:master from VijayabaskarR-06:fix-install-prefix changing 1 files +5 −1

VijayabaskarR-06 commented at 9:05 AM on October 7, 2026: none

Fixes #134.

mpgen was looking for proxy.capnp using the path from when libmultiprocess was built. If the library was installed with a different prefix then the downstream builds failed with Import failed: /mp/proxy.capnp.

This change passes the installed include path from Libmultiprocess::mpgen to mpgen so it can find the file after installation.

Subdirectory builds and builds using MPGEN_EXECUTABLE are unchanged.

I tested this with Bitcoin Core's bitcoin_ipc target. It works with this change and also compared it with main !

cmake: Pass installed include dir to mpgen

mpgen finds /mp/proxy.capnp using the CMAKE_INSTALL_PREFIX that was set
when it was built. If libmultiprocess is installed somewhere else, for
example with `cmake --install build --prefix ~/.local`, or the install is
moved, code generation fails with "Import failed: /mp/proxy.capnp".

When target_capnp_sources uses the imported Libmultiprocess::mpgen
target, pass its include directory to mpgen as an import path. That path
comes from the installed package location, so it is correct wherever
the package ends up. Builds that use libmultiprocess as a subdirectory
already pass MP_INCLUDE_DIR and are unchanged.

Fixes #134

7239a977c3

DrahtBot commented at 9:05 AM on October 7, 2026: none



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#134 Installing in `${HOME}/.local` causes build error

cmake: Pass installed include dir to mpgen #375

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