Generally, symbolic information for parameters, local variables, and global variables is available for optimized programs. Type information about structs, unions, C++ classes, and the types and names of local variables, global variables, and parameters should be available.
Information about the location of parameters and local variables is sometimes missing for optimized code. If dbx cannot locate a value, it reports that it cannot. Sometimes the value might disappear temporarily, so try to single-step and print again.
The Oracle Solaris Studio 12.2 compilers and later Oracle Solaris Studio updates for SPARC based systems and x86 based systems provide the information for locating parameters and local variables. Newer versions of the GNU compilers also provide this information.
You can print global variables and assign values to them, although they might have inaccurate values if the final register-to-memory store has not happened yet.