JAjandeboevrie·Sep 30, 2023Submission
Dbg() – A macro for printf-style debugging fans
2 points · Open discussionsharkdp
dbg-macro
C++2019–2023
sharkdp / dbg-macro
dbg-macro
A dbg(…) macro for C++
4Distinct people
6Mentions
0Explicit recommenders
3.2KGitHub stars
What to know before exploring
What it is
A dbg(…) macro for C++
GitHub
Where it is used
No documented product use has been verified yet.
What people are saying
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Also in these discussions
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This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year6 dated mentions
Observed mentions: 2019-09-21 11:09:56 UTC to 2023-09-30 16:02:13 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 4 | 1 | 3 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 2 | 1 | 1 |
What Hacker News says
6 sourcesI've been using something similar lately for my "quick and dirty print debugging" needs [1]. It's much nicer and requires less effort than just using printf/cout. I feel like many of the critical comments here are missing that that's probably the intended use-case of this.
[1] https://github.com/sharkdp/dbg-macro
In Show HN: A C++ dump func. that can print multi-D vectors, maps, tuples, and allThank you for the feedback. No, it does not evaluate its argument twice - see this test: https://github.com/sharkdp/dbg-macro/blob/f30cdda9fc5332e062...
In Show HN: A dbg(...) macro for C++Thank you for the feedback. We deliberately chose not to do this (see discussion in https://github.com/sharkdp/dbg-macro/issues/26), mainly for the reasons given in the Rust documentation:
> The dbg! macro works exactly the same in release builds. This is useful when debugging issues that only occur in release builds or when debugging in release mode is significantly faster.
Note, however, that the C++ dbg(..) macro can be easily disabled to a no-op (identity-op, to be precise) with the DBG_MACRO_DISABLE flag.
In Show HN: A dbg(...) macro for C++Would be nice to offer runtime enable/disable. Out of curiosity, I wrote a little benchmark and submitted as a PR: https://github.com/sharkdp/dbg-macro/pull/57
The key idea is that modern CPUs dynamically branch-predict-away if-statements that are rarely/never invoked, such as a dynamically disabled dbg() call.
With the performance difference magnified 10x by loop unrolling, this is what I'm seeing on my Mac laptop:
830000000 iterations in 3 secs = 2.76667e+08 iters/sec (compiled-out).
840000000 iterations in 3 secs = 2.8e+08 iters/sec (dynamically disabled).
And this is the worst case, where the whole program does nothing but call dbg() - real world programs contain lots of other real work, drowning the minute difference in performance, i.e. in a real program I doubt you'd see even 0.1% total performance difference, littering it with dyn
Read the rest
amic dbg() statements.
p.s. my C/C++ is pretty rusty - feedback welcome, but pls be kind.
Show HN: A dbg(...) macro for C++
162 points · Open discussion