Checking if jemalloc is present

CheckJEMalloc.rb

module CheckJEMalloc
  require 'ffi'
  extend FFI::Library
  def self.je_malloc_exists?(jemalloc_so = nil)
    if !jemalloc_so.nil? && !jemalloc_so.is_a?(String)
      puts "ArgumentError : Only strings allowed as arguments"
      return false
    end
    jemalloc_so = ENV.fetch('LD_PRELOAD','') if jemalloc_so.nil?

    if jemalloc_so.empty?
      puts "No jemalloc.so was given as an argument or LD_PRELOAD"
      return false
    end

    begin
      ffi_lib jemalloc_so
    rescue LoadError => e
      puts "LoadError : #{e}"
      return false
    end
    begin
      attach_function :je_malloc, [:int], :int
    rescue FFI::NotFoundError => e
      puts "FFI::NotFoundError : #{e}"
      return false
    end
    return true
  end
end

How To Use

A. Using LD_PRELOAD:

A.1. Run IRB/Ruby/etc. with LD_PRELOAD .
  env LD_PRELOAD=<PATH_TO_JEMALLOC> irb
  env LD_PRELOAD=<PATH_TO_JEMALLOC> ruby

A.2. Require/Source CheckJEMalloc.rb .
 
A.3. Run CheckJEMalloc.je_malloc_exists? .

B. Without LD_PRELOAD:

B.1. Run IRB/Ruby/etc.

B.2. Require/Source CheckJEMalloc.rb .

B.3. Run CheckJEMalloc.je_malloc_exists?(<PATH_TO_JEMALLOC>)