Find Possible Numerical Values of Enum Using GDB

Question

With an enum declared and instantiated like this:

enum test_enumeration
    {
        test1 = 4,
        test2 = 10,
        test3,
    };

test_enumeration test_enum;

I can call

(gdb) ptype test_enum

to get out

type = enum test_enumeration {test1 = 4, test2 = 10, test3}

This gives me the numerical value of test1 and test2 but NOT test3. If I call

(gdb) print (int)test3

GDB prints out the value 11. However I want to be able to get something like this:

type = enum test_enumeration {test1 = 4, test2 = 10, test3 = 11}

By printing out the entire type definition using test_enum.
Unfortunately

(gdb) ptype (int)test_enum

returns the the type as int and not the values.

Is there a way to print out the enum constants like this or an option that needs to be set to always display their numerical versions?

GDB V10.1

Answer 1

This will print out all the elements of an enum type. The executable needs to have been compiled with debuginfo.

$ cat print-enum.py
import gdb

class PrintEnumCmd(gdb.Command):
  """print all elements of the given enum type"""

  def __init__(self):
    super(PrintEnumCmd, self).__init__("print-enum", gdb.COMMAND_DATA, gdb.COMPLETE_EXPRESSION)

  def invoke(self, argstr, from_tty):
    typename = argstr
    if not typename or typename.isspace():
      raise gdb.GdbError("Usage: print-enum type")

    try:
      t = gdb.lookup_type(typename)
    except gdb.error:
      typename = "enum " + typename
      try:
        t = gdb.lookup_type(typename)
      except gdb.error:
        raise gdb.GdbError("type " + typename + " not found")

    if t.code != gdb.TYPE_CODE_ENUM:
      raise gdb.GdbError("type " + typename + " is not an enum")

    for f in t.fields():
      print(f.name, "=", f.enumval)

PrintEnumCmd()

$ gdb enu
Reading symbols from enu...done.
(gdb) source print-enum.py
(gdb) print-enum
Usage: print-enum type
(gdb) print-enum test<tab>
test1             test2             test3             test_enumeration
(gdb) print-enum test_enumeration
test1 = 4
test2 = 10
test3 = 11