pyrox.dev
1# FUSE {#sec-fuse}
2
3Some packages rely on
4[FUSE](https://www.kernel.org/doc/html/latest/filesystems/fuse.html) to provide
5support for additional filesystems not supported by the kernel.
6
7In general, FUSE software is primarily developed for Linux but many of them can
8also run on macOS. Nixpkgs supports FUSE packages on macOS, but it requires
9[macFUSE](https://osxfuse.github.io) to be installed outside of Nix. macFUSE
10currently isn't packaged in Nixpkgs, mainly because it includes a kernel
11extension, which isn't supported by Nix outside of NixOS.
12
13If a package fails to run on macOS with an error message similar to the
14following, it's a likely sign that you need to have macFUSE installed.
15
16 dyld: Library not loaded: /usr/local/lib/libfuse.2.dylib
17 Referenced from: /nix/store/w8bi72bssv0bnxhwfw3xr1mvn7myf37x-sshfs-fuse-2.10/bin/sshfs
18 Reason: image not found
19 [1] 92299 abort /nix/store/w8bi72bssv0bnxhwfw3xr1mvn7myf37x-sshfs-fuse-2.10/bin/sshfs
20
21Package maintainers may often encounter the following error when building FUSE
22packages on macOS:
23
24 checking for fuse.h... no
25 configure: error: No fuse.h found.
26
27This happens on autoconf-based projects that use `AC_CHECK_HEADERS` or
28`AC_CHECK_LIBS` to detect libfuse, and will occur even when the `fuse` package
29is included in `buildInputs`. It happens because libfuse headers throw an error
30on macOS if the `FUSE_USE_VERSION` macro is undefined. Many projects do define
31`FUSE_USE_VERSION`, but only inside C source files. This results in the above
32error at configure time because the configure script would attempt to compile
33sample FUSE programs without defining `FUSE_USE_VERSION`.
34
35There are two possible solutions for this problem in Nixpkgs:
36
371. Pass `FUSE_USE_VERSION` to the configure script by adding
38 `CFLAGS=-DFUSE_USE_VERSION=25` in `configureFlags`. The actual value would
39 have to match the definition used in the upstream source code.
402. Remove `AC_CHECK_HEADERS` / `AC_CHECK_LIBS` for libfuse.
41
42However, a better solution might be to fix the build script upstream to use
43`PKG_CHECK_MODULES` instead. This approach wouldn't suffer from the problem that
44`AC_CHECK_HEADERS`/`AC_CHECK_LIBS` has at the price of introducing a dependency
45on pkg-config.