setup: constify settings passed to setup_func

setup_func isn't formally defined for libtil, but
setup_interactively() defacto establishes it and
til_module_t.setup() reflects the same signature and calling
convention except with til_settings_t constified.

This change makes them all consistent in this regard, but there
should probably be a formal typedef added for the function.

The reason for constifying this is I don't want setup functions
directly manipulating the settings instance.  In the case of
rototiller::setup_interactively() we ensure the stdio-based
interactive setup is always the side doing the manipulation of
the settings.  For a libtil-user like glimmer, it's slightly
different beast with GTK+ in the loop, but by preventing the
setup_funcs from messing directly with the settings (instead
having to describe what they want done iteratively), the
front-end always gets its opportunity to maintain its state while
doing the described things.

Of course, this is mostly a lie, and within libtil the constified
til_settings_t gets cast away to modify it in places.  But
keeping that limited to within libtil is tolerable IMO.  We just
don't want to see such casts in module code.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/til.h b/src/til.h
index 49823ba..fabee0a 100644
--- a/src/til.h
+++ b/src/til.h
@@ -45,7 +45,7 @@ void til_get_modules(const til_module_t ***res_modules, size_t *res_n_modules);
 void til_module_render(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr);
 int til_module_create_context(const til_module_t *module, til_stream_t *stream, unsigned seed, unsigned ticks, unsigned n_cpus, const char *parent_path, til_setup_t *setup, til_module_context_t **res_context);
 til_module_context_t * til_module_destroy_context(til_module_context_t *context, til_stream_t *stream);
-int til_module_setup(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup);
+int til_module_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup);
 int til_module_randomize_setup(const til_module_t *module, unsigned seed, til_setup_t **res_setup, char **res_arg);
 int til_fragmenter_slice_per_cpu(til_module_context_t *context, const til_fb_fragment_t *fragment, unsigned number, til_fb_fragment_t *res_fragment);
 int til_fragmenter_tile64(til_module_context_t *context, const til_fb_fragment_t *fragment, unsigned number, til_fb_fragment_t *res_fragment);