How can I change the value of a variable while debugging?

Question

I know that I can output the value of a variable using

(gdb) p var_name
$1 = "varvalue"

Is there a way to set the value of a variable while debugging with gdb? The document that I'm using doesn't seem to have this command.

Edit

I've since learned that I can change the state of objects in memory by simply calling their functions! So to modify an object of type std::string, just call the assign function as follows:

(gdb) call str.assign("New Value")

Thank you.

Answer 1

Google is your friend:

For example, if your program has a variable width, you get an error if you try to set a new value with just `set width=13', because GDB has the command set width:

(gdb) whatis width  
type = double   
(gdb) p width $4 = 13  
(gdb) set width=47  
Invalid syntax in expression. 

The invalid expression, of course, is `=47'. In order to actually set the program's variable width, use

(gdb) set var width=47

You can find the needed information in the following document:

Answer 2

A little bit later but to set a string variable you should try this>

gdb set var string_variable = 'new_string_variable'

Character numbers must be the same for the two variable definitions, in order to apply the change as appropriate. Quotes need to be applied to new variable.