update readme

README.md

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 # racket-static
 
 a base set of scripts that let you build fully self-contained static binaries for racket
-applications. this is better than raco exe/raco dist because that tooling can generate distribution
-folders that still depend on dynamic libraries the target system might not have, and it's also a
-whole folder instead of one easily distributable file
+applications
+
+depending on your needs, this can be preferred to the usual `raco exe`/`raco dist` because that
+tooling can generate distribution folders that still depend on dynamic libraries the target system
+might not have (actually, i was prompted to make this partially by someone running into this exact
+problem on mastodon). additionally, one single binary can be more convenient to distribute than a
+whole `dist` folder structure
 
 ## dependencies
 
@@ -12,6 +16,22 @@ whole folder instead of one easily distributable file
  - rsync (copying files into container)
  - wget (downloading stuff)
 
+## limitations
+
+because the runtime is hosted in a static binary, dynamic ffi is unavailable (eg, `ffi-lib`) will
+not work. the workaround for this currently provided is static ffi, where loading `table` from
+`static-ffi` (a primitive module instatiated by the runtime wrapper) will produce a table of
+available static ffi functions - the integer pointer will need to be `cast` to the correct function
+type but after that it works as expected  
+further work will automate the generation and loading of static ffi tables, ideally out of C headers
+using `c-utils`
+
+currently if the racket code runs into an error it segfaults. i think i have to register a handler
+for this but idk how the internals work
+
+runtime include paths probably don't work as expected. i have not tested but ideally don't use
+those yet
+
 ## hello world demo
 
 first time you run make it'll take a while. be patient. having more cores helps