Sun Studio 12: Debugging a Program With dbx

access mode address-expression [, byte-size-expression]

The memory specified by address-expression has been accessed.

mode specifies how the memory was accessed. It can be composed of one or all of the letters:


The memory at the specified address has been read.


The memory has been written to.


The memory has been executed.

mode can also contain either of the following:


Stops the process after the access (default).


Stops the process before the access.

In both cases the program counter will point at the offending instruction. The “before” and “after” refer to the side effect.

address-expression is any expression that can be evaluated to produce an address. If you give a symbolic expression, the size of the region to be watched is automatically deduced; you can override it by specifying byte-size-expression. You can also use nonsymbolic, typeless address expressions; in which case, the size is mandatory. For example:

stop access w 0x5678, sizeof(Complex)

The access command has the limitation that no two matched regions may overlap.

Note –

The access event specification is a replacement for the modify event specification.