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I have built GDB from source on macOS 12.0 and codesigned it. However, every time I try to debug a program, I get this:

(gdb) b main Breakpoint 1 at 0x10000324f: file main.cpp, line 50. (gdb) run Starting program: /Users/fluzzlesnuff/Documents/C++/a.out [New Thread 0x2a03 of process 2389]

and then GDB hangs. I have been compiling C++ programs with g++. Here are some things I have tried:

  1. Compile with -g option.
  2. Compile with -ggdb option.
  3. Compile with -ggdb3 option.
  4. Run with sudo
  5. Kill and re-run gdb repeatedly.
  6. Try different binaries.
  7. Disable SIP
  8. Add more breakpoints.
  9. set startup-with-shell off in .gdbinit

I do not get taskgated / Mach Port errors; only the New Thread message.

I realize that this is a near-duplicate of this, but I didn't see a working answer on that question.

For reference, here are my versions:

$ g++ --version Apple clang version 12.0.0 (clang-1200.0.32.29) Target: x86_64-apple-darwin21.0.0 Thread model: posix InstalledDir: /Library/Developer/CommandLineTools/usr/bin 
$ gdb --version GNU gdb (GDB) 10.2
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  • As you are using clang it might be a better idea to use lldb (as used in Xcode) as the debugger. I think gdb is more aligned to use with GNU cc which your g++ is not Commented Oct 31, 2021 at 14:51
  • g++ is an alias of gcc with some C++ options, so it’s definitely GNU. gcc.gnu.org Commented Nov 1, 2021 at 15:27
  • That is not what you show in the question the result of g++ --version says it isclang Commented Nov 1, 2021 at 22:15
  • I was kind of wondering about that. I just learned that g++ is really clang++ in disguise. This is likely the source of my problems. Commented Nov 2, 2021 at 4:10
  • 1
    If you're amenable to using lldb you can sidestep this altogether and have a working debugger. I wasn't able to get gdb working and hit this same error. No such issue with lldb which provides very similar functionality. Commented May 6, 2022 at 5:54

3 Answers 3

Reset to default
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As usual, attention to detail was the issue. I saw that g++ --version reported clang, but I didn’t think about it enough. I had assumed that GDB was the problem, not my compiler. I’m not sure why Apple linked g++ to clang++, since that’s quite misleading. This little oversight made me spend 8 months writing C++ on my phone (vi on a 60-character wide display is not my ideal IDE).

What I did to get real g++:

  1. Install gcc with Homebrew

  2. Soft-link (ln -s) gcc-11 and g++-11 from /usr/local/Cellar/ to /usr/local/bin/

  3. unhash (at least in zsh) gcc and g++, or else gcc will continue to expand to /usr/bin/clang

GDB is working great now.

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  • Why do you need gnu c++? Clang does most things as well and for macos and ios it is probably better. With clang you can use xcode which is a lot better ide than vi on an iPhone. Also doing most work in c you do not call gcc or clang on the command line but a build system eg make and for hat you want to se CC to the full path and don't rely on your $PATH Commented Nov 3, 2021 at 10:35
  • I’m not able to debug programs compiled with clang using gdb. I tried using Xcode, but it was much more than I needed for writing small utilities. I’m writing command-line utilities, so I find it easiest to g++ *.cpp, then run a.out with whatever arguments I desire. Commented Nov 3, 2021 at 14:44
  • Then use lldb to debug Commented Feb 23, 2022 at 8:55
  • I am running into same issue despite following above steps. I am using GDB version 2.1 and using MacOS Monterey 12.6.1 Commented Dec 26, 2022 at 0:28
  • @TusharJadhav GDB 2.1 is very old; is there any reason you need to use such an old version? Commented Dec 27, 2022 at 2:49
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EDIT: It seems that I was wrong, it still only works sporadically, sometimes it hangs sometimes it doesn't. It just happened to work three times in a row after running this command :(

I had the same problem and fought for hours trying to install gdb on mac. Found this blog that said that I should not have run

sudo DevToolsSecurity -enable

which I never did. So I tried it and it worked. Another possible solution was to run gdb with sudo every time but I felt this was better. No idea why they worked but they did, I hope someone else finds this useful.

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  • I didn’t run this, but after a recent update to the Command Line Developer Tools, I was asked for Touch-ID confirmation when I started up gdb. That makes me think your command, or some form of it, was run during the update, and now does a security check when running developer tools. Commented Nov 2, 2021 at 4:41
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This hang hits gdb bug: https://sourceware.org/bugzilla/show_bug.cgi?id=24069

You can install gdb from this source with patch:

brew install --force --build-from-source domq/gdb/gdb # a patched version based on 10.1

or you can

brew update brew install gdb # use gdb 12.1

It works for me, and I found it from this link: https://gist.github.com/mike-myers-tob/9a6013124bad7ff074d3297db2c98247

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