Nullify

Disassociates pointers.

Declaration

Syntax

Nullify(expr* vars)

Arguments

Argument	Description
vars	the pointers to disassociate.

Return values

None.

Description

nullify(p) makes p point at nothing, which is not the same as deallocating what it pointed at. Afterwards PointerAssociated is false for it.

Examples

(Nullify
  :vars [
    (Var
      :v (SymbolRef 1 "p")
    )
  ]
)

It comes from this complete ASR text document:

(TranslationUnit
  :symtab (SymbolTable
    :id 0
    :symbols {
      "main" (Program
        :symtab (SymbolTable
          :id 1
          :symbols {
            "a" (Variable
              :parent_symtab 1
              :name "a"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Allocatable
                :type (Array
                  :type (Integer
                    :kind 4
                  )
                  :dims [
                    (dimension
                      :start nil
                      :length nil
                    )
                  ]
                  :physical_type :DescriptorArray
                )
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
            )
            "p" (Variable
              :parent_symtab 1
              :name "p"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Pointer
                :type (Integer
                  :kind 4
                )
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
            )
            "stat" (Variable
              :parent_symtab 1
              :name "stat"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Integer
                :kind 4
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
            )
          }
        )
        :name "main"
        :dependencies []
        :body [
          (Allocate
            :args [
              (alloc_arg
                :a (Var
                  :v (SymbolRef 1 "a")
                )
                :dims [
                  (dimension
                    :start (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :length (IntegerConstant
                      :n 10
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                  )
                ]
                :codims []
                :len_expr nil
                :sym_subclass nil
                :type nil
              )
            ]
            :stat (Var
              :v (SymbolRef 1 "stat")
            )
            :errmsg nil
            :source nil
          )
          (ReAlloc
            :args [
              (alloc_arg
                :a (Var
                  :v (SymbolRef 1 "a")
                )
                :dims [
                  (dimension
                    :start (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :length (IntegerConstant
                      :n 20
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                  )
                ]
                :codims []
                :len_expr nil
                :sym_subclass nil
                :type nil
              )
            ]
          )
          (ExplicitDeallocate
            :vars [
              (Var
                :v (SymbolRef 1 "a")
              )
            ]
          )
          (Nullify
            :vars [
              (Var
                :v (SymbolRef 1 "p")
              )
            ]
          )
          (ImplicitDeallocate
            :vars [
              (Var
                :v (SymbolRef 1 "a")
              )
            ]
          )
        ]
      )
    }
  )
  :items []
)

See Also

Associate, PointerNullConstant, PointerAssociated, ExplicitDeallocate