vmec_putenv.f

      SUBROUTINE vmec_putenv(ename, evalue, ierror)
      IMPLICIT NONE
      INTEGER :: ierror
      CHARACTER(LEN=*), INTENT(in) :: ename, evalue
      CHARACTER(LEN=LEN_TRIM(ename)+LEN_TRIM(evalue)+2) :: temp
      INTEGER, EXTERNAL :: putenv
 
      temp = trim(ename) // "=" // trim(evalue) // char(0)
 
      ierror = putenv(temp)
 
      END SUBROUTINE vmec_putenv