nix/doc/manual/rl-next/c-api.md

synopsis	issues	prs
C API: functions for locking and loading a flake	10435	12877 13098

This release adds functions to the C API for handling the loading of flakes. Previously, this had to be worked around by using builtins.getFlake. C API consumers and language bindings now have access to basic locking functionality.

It does not expose the full locking API, so that the implementation can evolve more freely. Locking is controlled with the functions, which cover the common use cases for consuming a flake:

• nix_flake_lock_flags_set_mode_check
• nix_flake_lock_flags_set_mode_virtual
• nix_flake_lock_flags_set_mode_write_as_needed
• nix_flake_lock_flags_add_input_override, which also enables virtual

This change also introduces the new nix-fetchers-c library, whose single purpose for now is to manage the (nix.conf) settings for the built-in fetchers.

More details can be found in the C API documentation.