Storage for a static variable is allocated by the Compiler and/or linker prior to program execution. Storage remains allocated throughout program execution.
Only one instance of a static variable's storage is allocated, regardless of whether the variable is declared in a recursive procedure. Values assigned to a static variable are retained between calls to the procedure in which the variable is declared.
All extents specified for static character string, 8-bit area variables, and array variables must be constants.
Static variables can be declared with the INTERNAL or EXTERNAL attribute. If neither attribute is specified, INTERNAL is assumed.
An internal static variable is known in its containing block and in all contained blocks, except those blocks in which the same name is redeclared. This is the normal scope rule that applies to all other variables.
An external static variable is known in its containing block and in all contained blocks, except those blocks in which the same name is redeclared. However, all declarations of the same name that have the EXTERNAL attribute, including those in separate modules of the program, share the same storage and must specify identical attributes, including any initial values. External static variables are known and shared by all program modules in a manner similar to the common variables of FORTRAN, except that each external static variable is shared independently of others.