Storage classes in C and C++

z/OS® Debugger supports the change and reference of all objects declared with the following storage classes:

auto
register
static
extern

Session variables declared during the z/OS Debugger session are also available for reference and change.

An object with auto storage class is available for reference or change in z/OS Debugger, provided the block where it is defined is active. Once a block finishes executing, the auto variables within this block are no longer available for change, but can still be examined using DESCRIBE ATTRIBUTES.

An object with register storage class might be available for reference or change in z/OS Debugger, provided the variable has not been optimized to a register.

An object with static storage class is always available for change or reference in z/OS Debugger. If it is not located in the currently qualified compile unit, you must specifically qualify it.

An object with extern storage class is always available for change or reference in z/OS Debugger. It might also be possible to reference such a variable in a program even if it is not defined or referenced from within this source file. This is possible provided z/OS Debugger can locate another compile unit (compiled with TEST(SYM)) with the appropriate definition.