C array size via gdb

Question

I know you can print an array in gdb , e.g.

(gdb) p *array@10

Is there a gdb command that can tell you its length, e.g. a handy shortcut to typing something like:

(gdb) p sizeof(array)/sizeof(int)

In the case where the array has been defined at compile time and you want to check it

hrkzmnm · Accepted Answer · 2012-01-13 11:00:17Z

22

You may use ptype to know the type of a symbol.

For int array[5],

(gdb) ptype array
type = int [5]

answered Jan 13, 2012 at 11:00

hrkzmnm

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Comments

Kevin · Accepted Answer · 2012-01-10 18:31:42Z

15

If it's actually defined as an array, e.g.

int array[5];

Then yes, you can use what you wrote, although a better and more general way is:

(gdb) p sizeof(array)/sizeof(*array)

This doesn't assume the type of the array.

If the variable is defined as a pointer, then no.

answered Jan 10, 2012 at 18:31

Kevin

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good point, that is more generic - i thought there may be some gdb shortcut for that? or possibly you can define your own somehow?

@Hiett Well, if you just print the array, it'll print all the values. Beyond that, I don't know.