How to switch gdb byte output grouping

Question

When I try to see what's inside stack space, I use the following command:

x/100x $sp

However, sometimes output is formatted like this, grouping by 4 bytes:

0xbffff0ac: 0x00000000  0xb7fbc000  0xb7fbc000  0xbffff4e8
...

While sometimes I get this:

0xbffff0ac: 00 00 00 00 00 c0 fb b7 00 c0 fb b7 e8 f4 ff bf

But I can't determine how to switch between these formats and how gdb desides which format to use for output. Any suggestions?

x/100b <address> provides bytes, x/100s <address> provides shorts, etc. Also see questions like What does the gdb 'x' command do?, Formatting on gdb examine memory and GDB examine data display format from 8 bytes in a row to 4 bytes. — jww
– jww, Commented Feb 13, 2018 at 12:57

Employed Russian · Accepted Answer · 2018-02-13 22:42:36Z

5

sometimes output is formatted like this
However, sometimes output is formatted like this

This is because the x command remembers the last size you used.

If you want particular size with your x, just specify it directly:

(gdb) x/100wx $sp

answered Feb 13, 2018 at 15:53

Employed Russian

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