Posts tagged ffi

I have a little Racket program that dependences racket/rsvg, so I install the racket/rsvg lib on my macOS using under command

raco pkg install -u rsvg

but when I then run the program, it produces some error messages

ffi-lib: couldn’t open “librsvg–2.2.dylib” (dlopen(librsvg–2.2.dylib, 6): image not found)

after check the racket’s ffi-lib doc, I fixed it, the follow is How I fix the problem. originally posted on github

I have the same problem, and when I checked the method ffi-lib doc, it explains how racket finds ffi lib path

If path is not an absolute path, look in each directory reported by get-lib-dirs; the default list is the result of (get-lib-search-dirs).

as the racket document describes, we can use the code under here to get the current lib search dirs

(require setup/dirs)
(get-lib-search-dirs)

on my computer the result is '(#<path:/Users/mywo/Library/Racket/7.9/lib> #<path:/usr/local/opt/Racket/lib>). and my librsvg lib path is /usr/local/Cellar/librsvg/2.48.8/lib/librsvg-2.2.dylib, which can find with homebrew

brew list librsvg

if you don’t have librsvg in you system, you can install it using Homebrew

brew install librsvg

the racket document shows we can config lib search dirs, follow the Installation Configuration and Search Paths I changed my racket config file /Applications/Racket v7.9/etc/config.rktd, add the 'lib-search-dirs' setting to it, and my program running correctly.

here is my config.rktd content

#hash((build-stamp . "")
      (catalogs . ("https://download.racket-lang.org/releases/7.9/catalog/" #f))
      (doc-search-url . "https://download.racket-lang.org/releases/7.9/doc/local-redirect/index.html")
      (lib-search-dirs . ("/usr/local/opt/librsvg/lib/" #f)))

racket ffi 使用相关说明

• http://prl.ccs.neu.edu/blog/2016/06/27/tutorial-using-racket-s-ffi/
• http://prl.ccs.neu.edu/blog/2016/06/29/tutorial-racket-ffi-part–2/
• http://prl.ccs.neu.edu/blog/2016/07/11/tutorial-racket-ffi-part–3/