TotalView Users Guide - CI Wiki

Changing a Variable’s Data Type
If you want, you can change a $void to another type. Similarly, you can
change any type to a $void to see the variable in decimal and hexadecimal
formats.
Viewing Instructions ($code Data Type)
TotalView uses the $code data type to display the contents of a location as
machine instructions. To look at disassembled code stored at a location,
dive on the location and change the type to $code. To specify a block of
locations, use $code[n], where n is the number of locations being displayed.
Viewing Opaque Data
An opaque type is a data type that could be hidden, not fully specified, or
be defined in another part of your program. For example, the following C
declaration defines the data type for p to be a pointer to struct foo, and
foo is not yet defined:
struct foo;
struct foo *p;
When TotalView encounters a variable with an opaque type, it searches for
a struct, class, union, or enum definition with the same name as the opaque
type. If TotalView doesn’t find a definition, it displays the value of the variable
using an opaque type name; for example:
(Opaque foo)
Some compilers do not store sufficient information for TotalView to locate
the type. This could be the reason why TotalView uses the opaque type.
You can tell TotalView to use the correct data type by having it read the
source file. For example, if TotalView is showing you (Opaque foo) and you
know that struct foo is defined in source file foo.c, use the File > Open
Source Command. While this command’s primary purpose is to tell TotalView
to display the file within the Process Window, it also causes TotalView to read
the file’s debugging information. As a side-effect, struct foo should now be
defined. Because TotalView now knows its definition, it can resolve the
opaque type.
Type-Casting Examples
This section contains three type-casting examples:
� Displaying Declared Arrays
� Displaying Allocated Arrays
� Displaying the argv Array
320 Chapter 14: Examining and Changing Data