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AUTOMATIC
and STATIC
attributesWith -fdec-static GNU Fortran supports the DEC extended attributes
STATIC
and AUTOMATIC
to provide explicit specification of entity
storage. These follow the syntax of the Fortran standard SAVE
attribute.
STATIC
is exactly equivalent to SAVE
, and specifies that
an entity should be allocated in static memory. As an example, STATIC
local variables will retain their values across multiple calls to a function.
Entities marked AUTOMATIC
will be stack automatic whenever possible.
AUTOMATIC
is the default for local variables smaller than
-fmax-stack-var-size, unless -fno-automatic is given. This
attribute overrides -fno-automatic, -fmax-stack-var-size, and
blanket SAVE
statements.
Examples:
subroutine f integer, automatic :: i ! automatic variable integer x, y ! static variables save ... endsubroutine
subroutine f integer a, b, c, x, y, z static :: x save y automatic z, c ! a, b, c, and z are automatic ! x and y are static endsubroutine
! Compiled with -fno-automatic subroutine f integer a, b, c, d automatic :: a ! a is automatic; b, c, and d are static endsubroutine