I'm trying to recreate a const char* filename parameter for code I have that needs it...The function I'm wrapping is the OpenCV C++ function "imread" it is below in the documentation. It is used to read an image(jpg etc) from a file and return a pointer to it
http://docs.opencv.org/modules/highgui/doc/reading_and_writing_images_and_vi...
first I need to wrap in C as below calling the const char* filename parameter as a String* the below cv_imread does compile on ubuntu trusty using g++. And the function works as intended using g++.
Mat* cv_imread(String* filename, int flags) { return new Mat(cv::imread(*filename, flags)); }
I wrap in Lisp like this:
(defcfun ("cv_imread" %imread) (:pointer mat) (filename (:pointer string*)) (flags :int))
When I usually create a (:pointer string*) parameter I do it like this
(window-name (foreign-alloc :string :initial-element "IMREAD Example"))
and it works to supply strings that aren't filenames but when I try to use a filename both absolute and relative paths it fails...it also fails using double forward slashes in the pathname.
Any advice is appreciated and btw Emacs /SBCL is my Lisp IDE
Mat* cv_imread(String* filename, int flags) { return new Mat(cv::imread(*filename, flags)); }
How is the String type defined in C? Also, why are you wrapping the C++ API rather than the C API?
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Joeish W -
Luís Oliveira