system_mod.f

      MODULE system_mod
 
      INTERFACE system
         SUBROUTINE vmec_system(cmd, error)
         CHARACTER(LEN=*), INTENT(in) :: cmd
         INTEGER, OPTIONAL :: error
         END SUBROUTINE vmec_system
      END INTERFACE
      
      INTERFACE chdir
         INTEGER FUNCTION vmec_chdir(path)
         CHARACTER(LEN=*), INTENT(in) :: path
         END FUNCTION vmec_chdir
      END INTERFACE
      
      INTERFACE getenv
         SUBROUTINE vmec_getenv(ename, evalue)
         CHARACTER(LEN=*) :: ename, evalue
         END SUBROUTINE vmec_getenv
      END INTERFACE
 
      INTERFACE putenv
         SUBROUTINE vmec_putenv(ename, evalue, ierror)
         CHARACTER(LEN=*) :: ename, evalue
         INTEGER :: ierror
         END SUBROUTINE vmec_putenv
      END INTERFACE
 
      INTERFACE pxffork
          SUBROUTINE pxffork_g (ipid, ierror)
          INTEGER :: ipid, ierror
          END SUBROUTINE pxffork_g
      END INTERFACE
 
      INTERFACE getpid
          SUBROUTINE vmec_getpid(ipid, ierror)
          INTEGER :: ipid, ierror
          END SUBROUTINE vmec_getpid
      END INTERFACE
 
      INTERFACE pxfwait
          SUBROUTINE pxfwait_g(istat, iretpid, ierror)
          INTEGER :: istat, iretpid, ierror
          END SUBROUTINE pxfwait_g
      END INTERFACE
 
      END MODULE system_mod