Method: AdLint::Cc1::VariableTable#storage_duration_of

Defined in:
lib/adlint/cc1/object.rb

#storage_duration_of(dcl_or_def) ⇒ Object 



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# File 'lib/adlint/cc1/object.rb', line 782

def storage_duration_of(dcl_or_def)
  # NOTE: The ISO C99 standard says;
  #
  # 6.2.2 Linkages of identifiers
  #
  # 1 An identifier declared in different scopes or in the same scope more
  #   than once can be made to refer to the same object or function by a
  #   process called linkage.  There are three kinds of linkage: external,
  #   internal, and none.
  #
  # 3 If the declaration of a file scope identifier for an object or a
  #   function contains the storage-class specifier static, the identifier
  #   has internal linkage.
  #
  # 4 For an identifier declared with the storage-class specifier extern in
  #   a scope in which a prior declaration of that identifier is visible,
  #   if the prior declaration specifies internal or external linkage, the
  #   linkage of the identifier at the later declaration is the same as the
  #   linkage specified at the prior declaration. If no prior declaration
  #   is visible, or if the prior declaration specifies no linkage, then
  #   the identifier has external linkage.
  #
  # 5 If the declaration of an identifier for a function has no
  #   storage-class specifier, its linkage is determined exactly as if it
  #   were declared with the storage-class specifier extern. If the
  #   declaration of an identifier for an object has file scope and no
  #   storage-class specifier, its linkage is external.
  #
  # 6 The following identifiers have no linkage: an identifier declared to
  #   be anything other than an object or a function; an identifier
  #   declared to be a function parameter; a block scope identifier for an
  #   object declared without the storage-class specifier extern.
  #
  # 6.2.4 Storage durations of objects
  #
  # 1 An object has a storage duration that determines its lifetime. There
  #   are three storage durations: static, automatic, and allocated.
  #   Allocated storage is described in 7.20.3.
  #
  # 3 An object whose identifier is declared with external or internal
  #   linkage, or with the storage-class specifier static has static
  #   storage duration. Its lifetime is the entire execution of the program
  #   and its stored value is initialized only once, prior to program
  #   startup.
  #
  # 4 An object whose identifier is declared with no linkage and without
  #   the storage-class specifier static has automatic storage duration.

  if sc_spec = dcl_or_def.storage_class_specifier and
      sc_spec.type == :EXTERN || sc_spec.type == :STATIC
    :static
  else
    current_scope.global? ? :static : :automatic
  end
end