Print multiple variables with one command in GDB

Question

I want to execute the very simple command

print var1, var2, var3, var4

in gdb to examine the values of the vars from time to time.

I don't want to use display because it clutters up my view.

How can I do this? Right now all I can do is:

p var1  
p var2  
p var3  
p var4

This thread looks like youtube comments :D P.S. 2021 yeye... — ScienceDiscoverer, Mar 27 '21 at 17:53
Looks like 2015 saw the fix...what are you guys complaining about? Perhaps the end of 2021 will see the end of this comment thread. — lmat - Reinstate Monica, Dec 10 '21 at 14:01

score 67 · Answer 1 · answered Mar 31 '15 at 11:30

67

You can simply do this

print {var1,var2,var3,var4}

This will do the job.

answered Mar 31 '15 at 11:30

vikasmk

14

I run into error `array elements must all be the same size`. – pevik Oct 06 '15 at 23:25
3

This is quick and easy, but only if they are all the same type, or you can cast them usefully to the same type. – Gem Taylor Feb 18 '19 at 18:57

score 46 · Answer 2 · answered Dec 10 '09 at 18:15

46

Use the printf command. It's a bit of a hassle, but it gives good control over the formatting. From the command line:

(gdb) help printf
printf "printf format string", arg1, arg2, arg3, ..., argn
This is useful for formatted output in user-defined commands.

The format string is like in C (%d for normal size ints, %s for null terminated strings, etc.).

answered Dec 10 '09 at 18:15

TGV

1

I like this answer. One niche problem with it is that it only supports up to 64-bit integers: `That operation is not available on integers of more than 8 bytes.` (GCC on AMD64 has emulated `__int128_t` on some platforms.) Of course, you can shift and cast. – Conrad Meyer Dec 12 '19 at 17:37

score 29 · Answer 3 · edited May 08 '15 at 19:07

29

Use Macros:

For example to continue to next break point and print

(gdb) define prm

Type commands for definition of prm. End with a line saying just end.

>continue
>print var1
>print var2
>print var3
>end

(gdb) prm
$5 = 0
$6 = 10
$7 = -1

edited May 08 '15 at 19:07

OhBeWise

answered May 08 '15 at 18:33

Manas Jagadev

score 2 · Answer 4 · answered Dec 10 '09 at 18:13

2

There may be a simpler solution, but you might be able to put together something using GDB macros: http://www.ibm.com/developerworks/aix/library/au-gdb.html

answered Dec 10 '09 at 18:13

Edward Loper

4 Answers4