(gdb) Type Checking
(gdb) Range Checking
An overview of type checking
Some languages, such as Modula-2, are strongly typed, meaning that
the arguments to operators and functions have to be of the correct type,
otherwise an error occurs. These checks prevent type mismatch errors
from ever causing any run-time problems. For example,
1 + 2 => 3
error--> 1 + 2.3
The second example fails because the `CARDINAL' 1 is not
type-compatible with the `REAL' 2.3.
For the expressions you use in GDB commands, you can tell the GDB
type checker to skip checking; to treat any mismatches as errors and
abandon the expression; or to only issue warnings when type mismatches
occur, but evaluate the expression anyway. When you choose the last of
these, GDB evaluates expressions like the second example above, but
also issues a warning.
Even if you turn type checking off, there may be other reasons
related to type that prevent GDB from evaluating an expression. For
instance, GDB does not know how to add an `int' and a `struct foo'.
These particular type errors have nothing to do with the language in
use, and usually arise from expressions, such as the one described
above, which make little sense to evaluate anyway.
Each language defines to what degree it is strict about type. For
instance, both Modula-2 and C require the arguments to arithmetical
operators to be numbers. In C, enumerated types and pointers can be
represented as numbers, so that they are valid arguments to mathematical
operators. Supported languages Support, for further details on
GDB provides some additional commands for controlling the type
`set check type auto'
Set type checking on or off based on the current working language.
Supported languages Support, for the default settings for
`set check type on'
`set check type off'
Set type checking on or off, overriding the default setting for the
current working language. Issue a warning if the setting does not
match the language default. If any type mismatches occur in
evaluating an expression while type checking is on, GDB prints a
message and aborts evaluation of the expression.
`set check type warn'
Cause the type checker to issue warnings, but to always attempt to
evaluate the expression. Evaluating the expression may still be
impossible for other reasons. For example, GDB cannot add numbers
Show the current setting of the type checker, and whether or not
GDB is setting it automatically.
(gdb) Range Checking
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