Assigning values to type casted vars

Assigning values to type casted vars

[Sascha]

Hi,

Eclipse CDT supports casting variables to a different type. This is done by
creating an MI var like this:

1466-var-create - * (int)myValue
1466^done,name="var35",numchild="0",value="1",type="int"

1467-var-show-attributes var35
1467^done,attr="editable"

The var is "editable". But in most cases GDB does report an error when
assigning a value to the var:

1472-var-assign var35 0x1234
1472^error,msg="mi_cmd_var_assign: Could not assign expression to varible
object"


The error occurs for most casts like int -> int, int -> char, char -> int,
... . It only seems to work for struct -> int, struct -> short int, ...
(most of the time).

Does this happen for reason, or should I raise a bug ?

Eclipse CDT bug:
https://bugs.eclipse.org/bugs/show_bug.cgi?id=73598

Sascha

Re: Assigning values to type casted vars

[Nick Roberts]

 > Eclipse CDT supports casting variables to a different type. This is done by
 > creating an MI var like this:
 > 
 > 1466-var-create - * (int)myValue
 > 1466^done,name="var35",numchild="0",value="1",type="int"
 > 
 > 1467-var-show-attributes var35
 > 1467^done,attr="editable"
 > 
 > The var is "editable". But in most cases GDB does report an error when
 > assigning a value to the var:
 >
 > 1472-var-assign var35 0x1234
 > 1472^error,msg="mi_cmd_var_assign: Could not assign expression to varible
 > object"

The fact that the var has the attribute "editable" is a bit of a red herring.
A value can't be assigned because (int)myValue isn't an lvalue.  You get the
same error if you do:

-var-create - * 2*myValue
^done,name="var36",numchild="0",value="2",type="int"

-var-assign var36 0x1234

I think it only makes sense to watch such values.

-- 
Nick                                           http://www.inet.net.nz/~nickrob