demo_regfree Program

     program demo_regfree
     use M_regex, only: regex_type, regcomp, regexec, regmatch, regfree, regerror
     implicit none
     integer                      :: istat
     type(regex_type)             :: regex
     character(len=:),allocatable :: expression
        expression= "([0-9\.\-\*\/]+)+"
        call regcomp(regex,expression,'x')
        if (istat/=0) then
          stop 'Regex runtime error: regcomp failed.'
        endif
        call regfree(regex)
     end program demo_regfree