The usual way to examine data in your program is with the print
command (abbreviated p), or its synonym inspect. It
evaluates and prints the value of an expression of the language your
program is written in (see section Using GDB with Different Languages).
print expr
print /fexpr
expr is an expression (in the source language). By default the
value of expr is printed in a format appropriate to its data type;
you can choose a different format by specifying `/f', where
f is a letter specifying the format; see Output formats.
print
print /f
If you omit expr, GDB displays the last value again (from the
value history; see section Value history). This allows you to
conveniently inspect the same value in an alternative format.
A more low-level way of examining data is with the x command.
It examines data in memory at a specified address and prints it in a
specified format. See section Examining memory.
If you are interested in information about types, or about how the
fields of a struct or a class are declared, use the ptype exp
command rather than print. See section Examining the Symbol Table.