# Questions / Help **URL:** https://erlangforums.com/c/erlang-questions/7.md?page=2 [Latest](https://erlangforums.com/latest.md) · [Categories](https://erlangforums.com/categories.md) · [Tags](https://erlangforums.com/tags.md) **Page:** 3 --- ## [Dialyzer warnings on match spec records and warnings from ignored functions](https://erlangforums.com/t/dialyzer-warnings-on-match-spec-records-and-warnings-from-ignored-functions/5441)
**Author:** [@lsund-sk](https://erlangforums.com/u/lsund-sk)\ **Replies:** 5\ **Last updated:** [February 25, 2026, 3:28pm UTC](https://erlangforums.com/t/dialyzer-warnings-on-match-spec-records-and-warnings-from-ignored-functions/5441 "2026-02-25T15:28:25Z")
I have a program that creates a match spec from a local record. -module(hello). -export(\[hello\_world/0\]). -record(item, { key :: \[binary()\] }). -spec hello\_world() -\> ok. hello\_world() -\> Key = \[~"foo", ~"… --- ## [How to create a release with the test dependencies?](https://erlangforums.com/t/how-to-create-a-release-with-the-test-dependencies/5452)
**Author:** [@NAR](https://erlangforums.com/u/NAR)\ **Replies:** 2\ **Last updated:** [February 25, 2026, 12:37pm UTC](https://erlangforums.com/t/how-to-create-a-release-with-the-test-dependencies/5452 "2026-02-25T12:37:20Z")
Hello! The Erlang project I’m working on is using rebar3. There are a few dependencies like meck that are only in the test profile, because they are only supposed to be used during local testing, i.e. after rebar3 as te… --- ## [Compiling Erlang for Android 16KB](https://erlangforums.com/t/compiling-erlang-for-android-16kb/4791)
**Author:** [@michi](https://erlangforums.com/u/michi)\ **Replies:** 4\ **Last updated:** [February 16, 2026, 10:12pm UTC](https://erlangforums.com/t/compiling-erlang-for-android-16kb/4791 "2026-02-16T22:12:12Z")
Hello together, does anybody compiled Erlang OTP 26 or higher for Android which is compatible for the new page size 16KB - like mentioned in Support 16 KB page sizes | Compatibility | Android Developers and any hin… --- ## [Any battle-tested ModBus/TCP library out there with proper network error resilience](https://erlangforums.com/t/any-battle-tested-modbus-tcp-library-out-there-with-proper-network-error-resilience/5432)
**Author:** [@Paddlaren](https://erlangforums.com/u/Paddlaren)\ **Replies:** 0\ **Last updated:** [February 14, 2026, 10:20am UTC](https://erlangforums.com/t/any-battle-tested-modbus-tcp-library-out-there-with-proper-network-error-resilience/5432 "2026-02-14T10:20:13Z")
Before I go bananas and refactor some old ModBus library I just want to ask if there are any well working and battle tested modbus over tcp libraries out there with (and this is important) well designed error handling fo… --- ## [Rebar3 dialyzer requires plt\_extra\_apps, even though they're in deps](https://erlangforums.com/t/rebar3-dialyzer-requires-plt-extra-apps-even-though-theyre-in-deps/5429)
**Author:** [@rlipscombe](https://erlangforums.com/u/rlipscombe)\ **Replies:** 1\ **Last updated:** [February 12, 2026, 8:56am UTC](https://erlangforums.com/t/rebar3-dialyzer-requires-plt-extra-apps-even-though-theyre-in-deps/5429 "2026-02-12T08:56:20Z")
I added cowboy and bbmustache to my project in the deps section of rebar.config. And I’m getting errors like the following: src/dashboard/dashboard.erl Line 9 Column 16: Unknown function cowboy\_router:compile/1 Line 21 … --- ## [OTP 25.3 Nodes Permanently Locked at 100% CPU: timerfd\_settime Dominates (48.5%) in Frame-Sync Game with 33ms Timers](https://erlangforums.com/t/otp-25-3-nodes-permanently-locked-at-100-cpu-timerfd-settime-dominates-48-5-in-frame-sync-game-with-33ms-timers/5427)
**Author:** [@jack001](https://erlangforums.com/u/jack001)\ **Replies:** 1\ **Last updated:** [February 12, 2026, 8:08am UTC](https://erlangforums.com/t/otp-25-3-nodes-permanently-locked-at-100-cpu-timerfd-settime-dominates-48-5-in-frame-sync-game-with-33ms-timers/5427 "2026-02-12T08:08:09Z")
Environment: 8-core 64GB server, Erlang 25.3, 30+ frame-synchronized game nodes. Symptoms: Stable CPU ≈ 3% initially Three nodes spiked to 100% CPU at 17:22/19:20/next day 12:30 and never recovered (unaffected by play… --- ## [Diameter Watchdog Algorithm](https://erlangforums.com/t/diameter-watchdog-algorithm/5424)
**Author:** [@cristconst](https://erlangforums.com/u/cristconst)\ **Replies:** 0\ **Last updated:** [February 11, 2026, 11:43pm UTC](https://erlangforums.com/t/diameter-watchdog-algorithm/5424 "2026-02-11T23:43:10Z")
Hi, A little bit of context… Diameter base protocol requires the usage of an application layer watchdog which is defined in the RFC 3539 - Authentication, Authorization and Accounting (AAA) Transport Profile , in this … --- ## [When is \`is\_process\_alive/1\` slow?](https://erlangforums.com/t/when-is-is-process-alive-1-slow/5401)
**Author:** [@zachallaun](https://erlangforums.com/u/zachallaun)\ **Replies:** 9\ **Last updated:** [February 5, 2026, 10:52am UTC](https://erlangforums.com/t/when-is-is-process-alive-1-slow/5401 "2026-02-05T10:52:31Z")
I’m looking for some insight into process “patterns” that can result in is\_process\_alive/1 (docs) being unexpectedly slow. For context, I have a singleton gen\_server that is responsible for monitoring many other process… --- ## [Best approach for high-frequency stock updates in Mnesia](https://erlangforums.com/t/best-approach-for-high-frequency-stock-updates-in-mnesia/5411)
**Author:** [@vrannangi](https://erlangforums.com/u/vrannangi)\ **Replies:** 0\ **Last updated:** [February 4, 2026, 3:56pm UTC](https://erlangforums.com/t/best-approach-for-high-frequency-stock-updates-in-mnesia/5411 "2026-02-04T15:56:01Z")
Hi all, I’m building an app using Erlang/Yaws with Mnesia. I have an item record that stores product info including stock quantity: -record(item, { id, % String store\_id, % String name, … --- ## [Rebar3 vm.args Not Working](https://erlangforums.com/t/rebar3-vm-args-not-working/5377)
**Author:** [@PCOM](https://erlangforums.com/u/PCOM)\ **Replies:** 4\ **Last updated:** [January 29, 2026, 1:46am UTC](https://erlangforums.com/t/rebar3-vm-args-not-working/5377 "2026-01-29T01:46:16Z")
Hi everyone! Wondering if anyone else is seeing the same issue as I am. While starting my app, I need to force a nodename, this is mainly so that my freeswitch instance can connect properly and data can flow back and fo… --- ## [Connecting two nodes using OTP28 with -proto\_dist inet\_tls](https://erlangforums.com/t/connecting-two-nodes-using-otp28-with-proto-dist-inet-tls/5387)
**Author:** [@elbrujohalcon](https://erlangforums.com/u/elbrujohalcon)\ **Replies:** 6\ **Last updated:** [January 22, 2026, 2:46pm UTC](https://erlangforums.com/t/connecting-two-nodes-using-otp28-with-proto-dist-inet-tls/5387 "2026-01-22T14:46:50Z")
The Problem (TL;DR) For reasons that I won’t get into right now :trade\_mark:, my system needs to use two Erlang nodes in the same machine, one running OTP24 and the other running OTP28. That, in itself, is not a big deal… --- ## [What happen to Riak-TS in OpenRiak and are there any plans?](https://erlangforums.com/t/what-happen-to-riak-ts-in-openriak-and-are-there-any-plans/5378)
**Author:** [@Paddlaren](https://erlangforums.com/u/Paddlaren)\ **Replies:** 1\ **Last updated:** [January 20, 2026, 12:21pm UTC](https://erlangforums.com/t/what-happen-to-riak-ts-in-openriak-and-are-there-any-plans/5378 "2026-01-20T12:21:07Z")
Hi, (Crossposted at OpenRiak GitHub discussions) I am evaluating practices for data storage in my Erlang echo system and Riak thus OpenRiak seems really nice. I am both seeking to store Key-Value data and Time Series d… --- ## [Are there any best practice or smart methods for signal consistancy between applications](https://erlangforums.com/t/are-there-any-best-practice-or-smart-methods-for-signal-consistancy-between-applications/5301)
**Author:** [@Paddlaren](https://erlangforums.com/u/Paddlaren)\ **Replies:** 3\ **Last updated:** [January 17, 2026, 6:52pm UTC](https://erlangforums.com/t/are-there-any-best-practice-or-smart-methods-for-signal-consistancy-between-applications/5301 "2026-01-17T18:52:38Z")
Hi, I am working on a rather small but distributed server in Erlang. I have a few gen\_server/gen\_statem that communicates for different roles. Yet this is a small server with 4 simple applications. During development I… --- ## [Examples of using eunit's 'with'?](https://erlangforums.com/t/examples-of-using-eunits-with/3470)
**Author:** [@rlipscombe](https://erlangforums.com/u/rlipscombe)\ **Replies:** 3\ **Last updated:** [January 16, 2026, 2:29pm UTC](https://erlangforums.com/t/examples-of-using-eunits-with/3470 "2026-01-16T14:29:59Z")
The documentation for with says it looks like this: {with, X::any(), \[AbstractTestFun::((any()) -\> any())\]} but meck uses it like this (simplified): meck\_test\_() -\> {foreach, fun setup/0, fun teardown/1, \[{with, \[T\]}… --- ## [What are the main reason for Erlang numbers not having infinity and nan](https://erlangforums.com/t/what-are-the-main-reason-for-erlang-numbers-not-having-infinity-and-nan/5359)
**Author:** [@Schultzer](https://erlangforums.com/u/Schultzer)\ **Replies:** 57\ **Last updated:** [January 14, 2026, 11:45am UTC](https://erlangforums.com/t/what-are-the-main-reason-for-erlang-numbers-not-having-infinity-and-nan/5359 "2026-01-14T11:45:51Z")
What are the main reason for Erlang numbers not having infinity and nan? --- ## [HTTPC: make request to non-standard HTTP methods](https://erlangforums.com/t/httpc-make-request-to-non-standard-http-methods/5331)
**Author:** [@lpil](https://erlangforums.com/u/lpil)\ **Replies:** 1\ **Last updated:** [January 12, 2026, 10:26am UTC](https://erlangforums.com/t/httpc-make-request-to-non-standard-http-methods/5331 "2026-01-12T10:26:37Z")
Hello friends! I’m trying to help some folks with with httpc, but we’ve got a bit stuck. HTTP (RFC 9110) specifies some standard methods (GET, POST, etc), but it permits other methods. WebDAV (RFC 4918) defines some ext… --- ## [Multiple nodes or supervisors?](https://erlangforums.com/t/multiple-nodes-or-supervisors/5369)
**Author:** [@dominic](https://erlangforums.com/u/dominic)\ **Replies:** 0\ **Last updated:** [January 12, 2026, 6:11am UTC](https://erlangforums.com/t/multiple-nodes-or-supervisors/5369 "2026-01-12T06:11:19Z")
Our game project using multiple nodes to run the same app, about 50 node in 4 core,16GB IMOP there are several disadvantages: more code and config memory cost code update more expensive and danger, every node have to … --- ## [Mocking timeouts?](https://erlangforums.com/t/mocking-timeouts/5365)
**Author:** [@rlipscombe](https://erlangforums.com/u/rlipscombe)\ **Replies:** 5\ **Last updated:** [January 9, 2026, 1:32pm UTC](https://erlangforums.com/t/mocking-timeouts/5365 "2026-01-09T13:32:35Z")
I’ve got a gen\_statem that uses timeout, event\_timeout, state\_timeout. I’d like to test it without waiting around until the timers actually expire. But nor do I want to set the timeouts to ridiculously short values, beca… --- ## [Building 28.3 with man pages via kerl](https://erlangforums.com/t/building-28-3-with-man-pages-via-kerl/5361)
**Author:** [@igorclark](https://erlangforums.com/u/igorclark)\ **Replies:** 0\ **Last updated:** [January 7, 2026, 9:57pm UTC](https://erlangforums.com/t/building-28-3-with-man-pages-via-kerl/5361 "2026-01-07T21:57:32Z")
Hi all! Trying to build 28.3 with man pages via kerl. I’ve got a working build with KERL\_BUILD\_DOCS=yes KERL\_INSTALL\_MANPAGES=yes CFLAGS="-O2 -g" kerl build 28.3 - it installs and runs fine, but it doesn’t seem to build… --- ## [Is it possible to get the remaining time of a gen\_statem state time-out?](https://erlangforums.com/t/is-it-possible-to-get-the-remaining-time-of-a-gen-statem-state-time-out/3722)
**Author:** [@lkuty](https://erlangforums.com/u/lkuty)\ **Replies:** 5\ **Last updated:** [January 7, 2026, 9:41pm UTC](https://erlangforums.com/t/is-it-possible-to-get-the-remaining-time-of-a-gen-statem-state-time-out/3722 "2026-01-07T21:41:10Z")
Is it possible to get the value (the remaining time) of a gen\_statem state time-out ? Note that I could store the datetime when hitting the state enter call and thus know the time elapsed since it is in the given state. --- ## [For wxListCtrl:insertItem/4 how to create imageIndex?](https://erlangforums.com/t/for-wxlistctrl-insertitem-4-how-to-create-imageindex/5345)
**Author:** [@kanga-roo](https://erlangforums.com/u/kanga-roo)\ **Replies:** 2\ **Last updated:** [January 6, 2026, 2:46am UTC](https://erlangforums.com/t/for-wxlistctrl-insertitem-4-how-to-create-imageindex/5345 "2026-01-06T02:46:21Z")
As I understand it; In the context of wxListCtrl’s insertItem method, ImageIndex refers to the index of the image associated with the item being inserted. This index is used to specify which image from the image list s… --- ## [Is it possible to build erlang with rebar3 without offering the erlang run time?](https://erlangforums.com/t/is-it-possible-to-build-erlang-with-rebar3-without-offering-the-erlang-run-time/5346)
**Author:** [@omar](https://erlangforums.com/u/omar)\ **Replies:** 3\ **Last updated:** [January 1, 2026, 9:39am UTC](https://erlangforums.com/t/is-it-possible-to-build-erlang-with-rebar3-without-offering-the-erlang-run-time/5346 "2026-01-01T09:39:19Z")
Hey guys. Beginner in erlang here. I was wondering if it is possible to use rebar3 in a way that the machine having the tool built in erlang, wouldn’t be able to run something like “console” and obtain information abou… --- ## [Recommended way to do somethink like subtyping?](https://erlangforums.com/t/recommended-way-to-do-somethink-like-subtyping/5336)
**Author:** [@jpellegrini](https://erlangforums.com/u/jpellegrini)\ **Replies:** 7\ **Last updated:** [December 25, 2025, 4:58pm UTC](https://erlangforums.com/t/recommended-way-to-do-somethink-like-subtyping/5336 "2025-12-25T16:58:48Z")
Hello, While researching how to implement subtyping, I was misled by some Artificial Intelligence systems to believe that I can do this: -type person() :: #{name =\> string()}. -type employee() :: person()#{salary =\> … --- ## [How to merge multiple beam files into one beam?](https://erlangforums.com/t/how-to-merge-multiple-beam-files-into-one-beam/5339)
**Author:** [@dominic](https://erlangforums.com/u/dominic)\ **Replies:** 2\ **Last updated:** [December 25, 2025, 7:25am UTC](https://erlangforums.com/t/how-to-merge-multiple-beam-files-into-one-beam/5339 "2025-12-25T07:25:12Z")
I’m using .beam as script file, then I can hidden my code and run every where. Usually, there are multiple files work together like: main.erl util.erl .... Is it possible to merge multiple beam files into one beam? W… --- ## [Compiling Erlang OS for different operating systems](https://erlangforums.com/t/compiling-erlang-os-for-different-operating-systems/5324)
**Author:** [@michi](https://erlangforums.com/u/michi)\ **Replies:** 2\ **Last updated:** [December 24, 2025, 12:28pm UTC](https://erlangforums.com/t/compiling-erlang-os-for-different-operating-systems/5324 "2025-12-24T12:28:25Z")
Hello together, just to discuss or getting some hints for compiling erlang directly from GitHub for different operating systems. How do you compiling a erlang releases for specific operating systems, e.g. OTP-28.3 for … --- ## [Leex documentation tells me to use a function whose documentation says I shouldn't use it](https://erlangforums.com/t/leex-documentation-tells-me-to-use-a-function-whose-documentation-says-i-shouldnt-use-it/5321)
**Author:** [@jpellegrini](https://erlangforums.com/u/jpellegrini)\ **Replies:** 3\ **Last updated:** [December 22, 2025, 4:15am UTC](https://erlangforums.com/t/leex-documentation-tells-me-to-use-a-function-whose-documentation-says-i-shouldnt-use-it/5321 "2025-12-22T04:15:52Z")
Hello! I am beginning to write some Erlang code, and decided to write a simple lexer (without a parser attached) using leex, and found the documentation a bit confusing. I know the lexer produced by leex creates the fu… --- ## [Elixir-dbvisor/sql Needs a SOTA pool and I want to hear your ideas](https://erlangforums.com/t/elixir-dbvisor-sql-needs-a-sota-pool-and-i-want-to-hear-your-ideas/5145)
**Author:** [@Schultzer](https://erlangforums.com/u/Schultzer)\ **Replies:** 8\ **Last updated:** [December 22, 2025, 12:06am UTC](https://erlangforums.com/t/elixir-dbvisor-sql-needs-a-sota-pool-and-i-want-to-hear-your-ideas/5145 "2025-12-22T00:06:05Z")
So the day has come, and due to unforeseen technical issues, then SQL - Brings an extensible SQL parser and sigil to Elixir, confidently write SQL with automatic parameterized queries. - Libraries - Elixir Programming La… --- ## [Setting up tracing for a future process: how?](https://erlangforums.com/t/setting-up-tracing-for-a-future-process-how/5316)
**Author:** [@gmile](https://erlangforums.com/u/gmile)\ **Replies:** 2\ **Last updated:** [December 16, 2025, 7:45am UTC](https://erlangforums.com/t/setting-up-tracing-for-a-future-process-how/5316 "2025-12-16T07:45:27Z")
Hi! How does one sets up tracing for a future short-lived process pid, that doesn’t exist yet? Ideally, on a live production system, without direct code modification & in-memory module reloading. For context, I am look… --- ## [Moduledoc attribute elp tree-sitter highlights - are there any options that could fix/improve -moduledoc highlighting / spell checking?](https://erlangforums.com/t/moduledoc-attribute-elp-tree-sitter-highlights-are-there-any-options-that-could-fix-improve-moduledoc-highlighting-spell-checking/5238)
**Author:** [@andrzej-mag](https://erlangforums.com/u/andrzej-mag)\ **Replies:** 3\ **Last updated:** [December 15, 2025, 4:29pm UTC](https://erlangforums.com/t/moduledoc-attribute-elp-tree-sitter-highlights-are-there-any-options-that-could-fix-improve-moduledoc-highlighting-spell-checking/5238 "2025-12-15T16:29:45Z")
Define Erlang -moduledoc: -moduledoc "Test: \`12345\`". Similarly define Elixir @moduledoc: @moduledoc "Test: \`12345\`" Inspecting 12345 embedded code snippet gives the following highlight groups: Erlang: - @attri… --- ## [Wxdemo crashes on gl tab (macos)](https://erlangforums.com/t/wxdemo-crashes-on-gl-tab-macos/4855)
**Author:** [@fgarau](https://erlangforums.com/u/fgarau)\ **Replies:** 16\ **Last updated:** [December 12, 2025, 8:29am UTC](https://erlangforums.com/t/wxdemo-crashes-on-gl-tab-macos/4855 "2025-12-12T08:29:09Z")
I am an erlang/Elixir newbee and playing with wx:demo() on the latest macos (15.5) it crashes with the below error when selecting the open gl demo: 1\> wx:demo(). ok =CRASH REPORT==== 29-Jun-2025::09:45:34.206778 === c… [Previous page](https://erlangforums.com/c/erlang-questions/7.md?page=1) [Next page](https://erlangforums.com/c/erlang-questions/7.md?page=3)