"lambert_W0" <- function(x,give=FALSE,strict=TRUE){
  attr <- attributes(x)
  x.vec <- as.vector(x)
  jj <- .C("lambert_W0",
           as.double(x.vec),
           as.integer(length(x.vec)),
           val=as.double(x.vec),
           err=as.double(x.vec),
           status=as.integer(0*x.vec),
           PACKAGE="gsl"
           )
  val <- jj$val
  err <- jj$err
  status <- jj$status
  attributes(val) <- attr
  attributes(err) <- attr  
  attributes(status) <- attr

  if(strict){
    val <- strictify(val,status)
  }
  if(give){
    return(list(val=val,err=err,status=status))
  } else {
    return(val)
  }  
} 

"lambert_Wm1" <- function(x,give=FALSE,strict=TRUE){
  attr <- attributes(x)
  x.vec <- as.vector(x)
  jj <- .C("lambert_Wm1",
           as.double(x.vec),
           as.integer(length(x.vec)),
           val=as.double(x.vec),
           err=as.double(x.vec),
           status=as.integer(0*x.vec),
           PACKAGE="gsl"
           )
  val <- jj$val
  err <- jj$err
  status <- jj$status
  attributes(val) <- attr
  attributes(err) <- attr  
  attributes(status) <- attr

  if(strict){
    val <- strictify(val,status)
  }
  if(give){
    return(list(val=val,err=err,status=status))
  } else {
    return(val)
  }  
} 
