gdb /x command on var vs *var

Question

I am learning GDB. When I run the x /3b command to see a 3-byte char array, I get two different outputs depending on if I put a * before the array name.

(gdb) x /3b myThreeCharArray
0x7fffffffe3c0: 4   11  64
(gdb) x /3b *myThreeCharArray
0x400b04 <debug>:   85  72  -119

What the difference between these two outputs? My understanding is that the x command will show you the bytes in memory represented by a particular variable. So I guess I thought that the x command inherently "dereferences" the variable name, but apparently that is not the case. What's going on?

Answer 1

In gdb the x command takes an address and attempts to print values from that memory location. So in the second case you dereference myThreeCharArray and produce a value which gdb interprets as an address and attempts to print the memory at that "location". You can see this is the case if you convert your first 3 numbers to hex:

64 is 0x40
11 is 0x0B
04 is 0x04

The order is switched because of endianness.