Test valgrind

Author: ankane

.github/workflows/build.yml

@@ -16,4 +16,5 @@ jobs:
       - if: ${{ startsWith(matrix.os, 'macos') }}
         run: brew install libomp
       - run: bundle exec rake vendor:all
-      - run: bundle exec rake test
+      - run: sudo apt-get update && sudo apt-get install valgrind
+      - run: valgrind --leak-check=yes bundle exec rake test

lib/thundersvm/model.rb

@@ -158,7 +158,7 @@ def create_dataset(x, y = nil)
     end
 
     def str_ptr(arr)
-      ptr = Fiddle::Pointer.malloc(Fiddle::SIZEOF_VOIDP * arr.size, Fiddle::RUBY_FREE)
+      ptr = Fiddle::Pointer.malloc(Fiddle::SIZEOF_VOIDP * arr.size)
       str_ptrs = arr.map { |v| Fiddle::Pointer["#{v}\x00"] }
       str_ptrs.each_with_index do |v, i|
         ptr[i * Fiddle::SIZEOF_VOIDP, Fiddle::SIZEOF_VOIDP] = v.ref