SPDX-License-Identifier: CC-BY-SA-4.0
copyrights:
- Copyright (C) 2020 embedded brains GmbH & Co. KG
enabled-by: true
functional-type: function
links:
- role: interface-function
  uid: ../if/zero-length-array
rationale: |
  From GNU C documentation:

    Although the size of a zero-length array is zero, an array member of this
    kind may increase the size of the enclosing type as a result of tail padding.

    Example::

      struct line
      {
        int length;
        char contents[RTEMS_ZERO_LENGTH_ARRAY];
      };

      struct line *thisline = (struct line *)
        malloc (sizeof (struct line) + this_length);
      thisline->length = this_length;

  Zero-length arrays and especially objects ending with zero-length arrays
  can be statically initialized so that they are larger than declared (have more
  that 0 elements). See the documentation of the GNU C compiler
  below keyword: *arrays of length zero*.
references: []
requirement-type: functional
text: |
  When the code is compiled with the GNU C compiler,
  and the ${../if/zero-length-array:/name} macro is used as
  element count of an array declaration,
  and that array declaration is the last member of a ``struct`` that is
  otherwise non-empty,
  and that structure is never used as member of another structure or
  array,
  the macro shall cause the compiler to layout the structure as if the
  array had an element count of one but to reduce the total size
  of the structure by the size of that one array element.
type: requirement