# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=7

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**Page:** 8

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## [How to understand reasons for some unexpected heap allocations](https://discourse.julialang.org/t/how-to-understand-reasons-for-some-unexpected-heap-allocations/137645)

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**Author:** [@user664303](https://discourse.julialang.org/u/user664303)\
**Replies:** 25\
**Last updated:** [June 19, 2026, 1:47pm UTC](https://discourse.julialang.org/t/how-to-understand-reasons-for-some-unexpected-heap-allocations/137645 "2026-06-19T13:47:16Z")

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I’m really surprised by some heap allocations being made within a package I maintain. I don’t expect them because: I’ve use Cthulhu to ensure that all variables in the code are concretely typed. The variables in questi…

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## [How to suppress JETLS warnings](https://discourse.julialang.org/t/how-to-suppress-jetls-warnings/137649)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 1\
**Last updated:** [June 18, 2026, 2:49pm UTC](https://discourse.julialang.org/t/how-to-suppress-jetls-warnings/137649 "2026-06-18T14:49:50Z")

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In general, JETLS helps a lot. But some warnings I would like to suppress, for example this one: \`ADD\_MIRROR\` is not concretized but JET needs to use its actual value in order to define types or methods. - If this bin…

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## [Benchmarking a value dependent function](https://discourse.julialang.org/t/benchmarking-a-value-dependent-function/137683)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 1\
**Last updated:** [June 18, 2026, 11:11am UTC](https://discourse.julialang.org/t/benchmarking-a-value-dependent-function/137683 "2026-06-18T11:11:06Z")

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I have a package that, at its core, performs a calculation f(P, x) for various values of x, using various user-defined methods for problem P and inputs x. The key is that even though all the components are type-stable,…

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## [Performance issue after upgrade from Julia 1.9.3 to 1.10.11](https://discourse.julialang.org/t/performance-issue-after-upgrade-from-julia-1-9-3-to-1-10-11/137657)

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**Author:** [@rdl987](https://discourse.julialang.org/u/rdl987)\
**Replies:** 6\
**Last updated:** [June 18, 2026, 8:39am UTC](https://discourse.julialang.org/t/performance-issue-after-upgrade-from-julia-1-9-3-to-1-10-11/137657 "2026-06-18T08:39:42Z")

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I’m migrating my project from julia 1.9.3 to 1.10.11 and I’m experiencing a huge quantity of time in gc. I benchmarked a function that performs arrow files reads from an s3 bucket an the @time with Julia 1.10.11 report …

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## [Bijou64 varint encoding](https://discourse.julialang.org/t/bijou64-varint-encoding/137654)

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**Author:** [@KyleSJohnston](https://discourse.julialang.org/u/KyleSJohnston)\
**Replies:** 5\
**Last updated:** [June 18, 2026, 5:53am UTC](https://discourse.julialang.org/t/bijou64-varint-encoding/137654 "2026-06-18T05:53:04Z")

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I recently discovered the bijou64 variable-length integer encoding. The reference implementation is in Rust, and it appears to outperform LEB128 for most encoding and decoding. While I don’t have any need for bijou64 in …

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## [Non-allocating way to parse section of string as number?](https://discourse.julialang.org/t/non-allocating-way-to-parse-section-of-string-as-number/137672)

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**Author:** [@AwesomeQuest](https://discourse.julialang.org/u/AwesomeQuest)\
**Replies:** 2\
**Last updated:** [June 17, 2026, 8:31pm UTC](https://discourse.julialang.org/t/non-allocating-way-to-parse-section-of-string-as-number/137672 "2026-06-17T20:31:57Z")

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Given a big string with numbers in it like input = ";(,)\<mul(595,110)~ #(select()-?who():mul(732,729)+/;%@mul(924,700)" and I know at execution time exactly where a number is in the string, I can parse that section of …

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## [Upwinding in Gridap](https://discourse.julialang.org/t/upwinding-in-gridap/127571)

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**Author:** [@Simons](https://discourse.julialang.org/u/Simons)\
**Replies:** 1\
**Last updated:** [June 17, 2026, 1:48pm UTC](https://discourse.julialang.org/t/upwinding-in-gridap/127571 "2026-06-17T13:48:27Z")

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Hi all, I want to solve an advection-diffusion problem with DG and upwinding. Specifically, I need to define the form f1(u,v) = ∫( upwinded(u, b, n\_Λ) \* v )dΛ where upwinded(u, b, n\_Λ) = u.plus if dot(b, n\_\\Lambda.p…

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## [PromptingTools.jl and OpenRouter](https://discourse.julialang.org/t/promptingtools-jl-and-openrouter/137662)

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**Author:** [@KajWiik](https://discourse.julialang.org/u/KajWiik)\
**Replies:** 2\
**Last updated:** [June 17, 2026, 7:08am UTC](https://discourse.julialang.org/t/promptingtools-jl-and-openrouter/137662 "2026-06-17T07:08:41Z")

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I noticed that only selected OpenRouter models are available for PromptingTools.jl. How to use others e.g. the free ones for testing like openai/gpt-oss-120b:free?

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## [Package Primes.jl not work](https://discourse.julialang.org/t/package-primes-jl-not-work/137653)

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**Author:** [@mefi](https://discourse.julialang.org/u/mefi)\
**Replies:** 7\
**Last updated:** [June 17, 2026, 6:52am UTC](https://discourse.julialang.org/t/package-primes-jl-not-work/137653 "2026-06-17T06:52:31Z")

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For Julia 1.12.6 xxx cannot be found when loading the package Primes.jl. xxx: version 6.10.2+1 of package Qt6Base\_jll is not available. what can I do?

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## [Performance overhead of an indirection to basic array function](https://discourse.julialang.org/t/performance-overhead-of-an-indirection-to-basic-array-function/137663)

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**Author:** [@Tortar](https://discourse.julialang.org/u/Tortar)\
**Replies:** 0\
**Last updated:** [June 16, 2026, 11:38pm UTC](https://discourse.julialang.org/t/performance-overhead-of-an-indirection-to-basic-array-function/137663 "2026-06-16T23:38:19Z")

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I have a macro which creates these function indirections for very basic collection functions, i.e. it substitutes all Base.getindex instances with \_unchecked\_getindex: Base.@propagate\_inbounds @inline function \_unchecke…

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## [Why check\_allocs warns about reliability?](https://discourse.julialang.org/t/why-check-allocs-warns-about-reliability/137660)

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**Author:** [@Benny](https://discourse.julialang.org/u/Benny)\
**Replies:** 0\
**Last updated:** [June 16, 2026, 6:32pm UTC](https://discourse.julialang.org/t/why-check-allocs-warns-about-reliability/137660 "2026-06-16T18:32:38Z")

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The docstring for check\_allocs in AllocCheck.jl warns, in part: If you rely on allocation-free code for safety/correctness, it is not sufficient to verify check\_allocs in test code and expect that the corresponding cal…

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## [How strict are the Naming Guidelines?](https://discourse.julialang.org/t/how-strict-are-the-naming-guidelines/137652)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 6\
**Last updated:** [June 16, 2026, 5:03pm UTC](https://discourse.julialang.org/t/how-strict-are-the-naming-guidelines/137652 "2026-06-16T17:03:29Z")

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Hi, I would like to name a package iGMT.jl, but that clearly violates some of the Guiding Lines (first char must be a capital letter, name distance to other packages must be 3)? The i here stands for interactive and the…

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## [Merging disjoint NamedTuples](https://discourse.julialang.org/t/merging-disjoint-namedtuples/137650)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 3\
**Last updated:** [June 16, 2026, 1:10pm UTC](https://discourse.julialang.org/t/merging-disjoint-namedtuples/137650 "2026-06-16T13:10:54Z")

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I need a function that merges two NamedTuples, but throws an error if they have elements in common. Not unlike @generated function merge\_disjoint(a::NamedTuple{A}, b::NamedTuple{B}) where {A,B} AB = intersect(A, B) …

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## [PSA: sometimes keywords affect dispatch](https://discourse.julialang.org/t/psa-sometimes-keywords-affect-dispatch/137646)

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**Author:** [@MilesCranmer](https://discourse.julialang.org/u/MilesCranmer)\
**Replies:** 2\
**Last updated:** [June 15, 2026, 11:16pm UTC](https://discourse.julialang.org/t/psa-sometimes-keywords-affect-dispatch/137646 "2026-06-15T23:16:59Z")

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Did you know that keywords can actually affect method dispatch in Julia? The Julia docs say they don’t: Keyword arguments behave quite differently from ordinary positional arguments. In particular, they do not partici…

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## [Path to project](https://discourse.julialang.org/t/path-to-project/85299)

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**Author:** [@Kruxigt](https://discourse.julialang.org/u/Kruxigt)\
**Replies:** 4\
**Last updated:** [June 15, 2026, 11:17am UTC](https://discourse.julialang.org/t/path-to-project/85299 "2026-06-15T11:17:40Z")

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Hi good folks! I have tried googling for this for about 4 hours now. How do I get the base path to the current project (that is not a module) in Julia? Thanks!

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## [Symbolics Build Function and Display of Code in Pluto](https://discourse.julialang.org/t/symbolics-build-function-and-display-of-code-in-pluto/102395)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 3\
**Last updated:** [June 14, 2026, 2:11pm UTC](https://discourse.julialang.org/t/symbolics-build-function-and-display-of-code-in-pluto/102395 "2026-06-14T14:11:19Z")

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I’m trying to make an example Pluto notebook, showing how some Julia functions can be manipulated by Symbolics and Converted to C. This all looks nice. But I don’t know the syntax once the function has generated C code…

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## [Broken juliaup installation](https://discourse.julialang.org/t/broken-juliaup-installation/137567)

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**Author:** [@krcools](https://discourse.julialang.org/u/krcools)\
**Replies:** 1\
**Last updated:** [June 12, 2026, 10:59am UTC](https://discourse.julialang.org/t/broken-juliaup-installation/137567 "2026-06-12T10:59:51Z")

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Julia on our linux server stopped working. On some snooping around I found this weird path in the juliaup managed section of .profile: cat .profile \[\[ -r ~/.bash\_profile \]\] && . ~/.bash\_profile # \>\>\> juliaup initializ…

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## [Allocations with nested Jacobians with StaticArrays and ForwardDiff](https://discourse.julialang.org/t/allocations-with-nested-jacobians-with-staticarrays-and-forwarddiff/136789)

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**Author:** [@Albert\_de\_montserrat](https://discourse.julialang.org/u/Albert_de_montserrat)\
**Replies:** 8\
**Last updated:** [June 12, 2026, 10:27am UTC](https://discourse.julialang.org/t/allocations-with-nested-jacobians-with-staticarrays-and-forwarddiff/136789 "2026-06-12T10:27:27Z")

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I am working a code where we do some nested Jacobians with StaticArrays, however I do not seem to manage to get it done without some allocations due to some internal type instability. The MWE below shows the allocations…

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## [Using DifferentialEquations.jl with ghost cells](https://discourse.julialang.org/t/using-differentialequations-jl-with-ghost-cells/137561)

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**Author:** [@Lucas](https://discourse.julialang.org/u/Lucas)\
**Replies:** 3\
**Last updated:** [June 12, 2026, 10:08am UTC](https://discourse.julialang.org/t/using-differentialequations-jl-with-ghost-cells/137561 "2026-06-12T10:08:54Z")

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I’m trying to solve a few differential equations using the method of lines. I’m using a five-point laplacian and ghost cells. I will add some code below, for the case of an imaginary-time Gross-Pitaevskii equation with c…

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## [Recompilation of test project](https://discourse.julialang.org/t/recompilation-of-test-project/137552)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 17\
**Last updated:** [June 11, 2026, 10:29pm UTC](https://discourse.julialang.org/t/recompilation-of-test-project/137552 "2026-06-11T22:29:01Z")

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In the past, I put my test dependencies in the main Project.toml file in the \[extras\] section. Recently, I started to use sub-projects and a separate Project.toml file in the test folder. But now the packages are pre-c…

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## [Thread-safe implementation for simple counter/mean](https://discourse.julialang.org/t/thread-safe-implementation-for-simple-counter-mean/137542)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 21\
**Last updated:** [June 11, 2026, 3:58pm UTC](https://discourse.julialang.org/t/thread-safe-implementation-for-simple-counter-mean/137542 "2026-06-11T15:58:04Z")

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I have a callable which performs an iterative calculation, which is otherwise thread-safe. I would like to keep a statistic of the mean number of iterations that it used, and is thread-safe. Stylized code follows: muta…

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## [Does the interactive thread have due performance?](https://discourse.julialang.org/t/does-the-interactive-thread-have-due-performance/137568)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 1\
**Last updated:** [June 11, 2026, 3:54pm UTC](https://discourse.julialang.org/t/does-the-interactive-thread-have-due-performance/137568 "2026-06-11T15:54:51Z")

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I have 2 physical chips on my machine, each having 64 physical cores. So there are 2 \* 2 \* 64 = 256 virtual processors. julia\> Sys.cpu\_summary() AMD EPYC 7763 64-Core Processor: speed user ni…

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## [Installing Dowloads 1.7 on julia 1.10 installs v1.6](https://discourse.julialang.org/t/installing-dowloads-1-7-on-julia-1-10-installs-v1-6/137558)

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**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 2\
**Last updated:** [June 11, 2026, 2:08pm UTC](https://discourse.julialang.org/t/installing-dowloads-1-7-on-julia-1-10-installs-v1-6/137558 "2026-06-11T14:08:27Z")

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What is going on with this. I assume it is some kind of stdlib shenanigans? (@v1.10) pkg\> add Downloads@1.7 Updating registry at \`~/.julia/registries/General.toml\` Resolving package versions... Updating \`~/do…

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## [Julia CodecZLib fails while python succeeds](https://discourse.julialang.org/t/julia-codeczlib-fails-while-python-succeeds/137548)

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**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 9\
**Last updated:** [June 11, 2026, 12:23pm UTC](https://discourse.julialang.org/t/julia-codeczlib-fails-while-python-succeeds/137548 "2026-06-11T12:23:52Z")

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Hi all, I have been trying to read avro files to Julia using Avro.jl, and I have received an error. I have used Claude to find the error and create a MWE and he thinks that the problem is actually in CodecZLib. I have a…

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## [OOP-brained design patterns](https://discourse.julialang.org/t/oop-brained-design-patterns/135423)

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**Author:** [@foobar\_lv2](https://discourse.julialang.org/u/foobar_lv2)\
**Replies:** 3\
**Last updated:** [June 11, 2026, 5:35am UTC](https://discourse.julialang.org/t/oop-brained-design-patterns/135423 "2026-06-11T05:35:08Z")

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I recently found myself writing julia code while somewhat OOP-brained. Surprisingly, the following design pattern works pretty well, so I want to share it for comments: # or mutable struct struct Base{Ext} baseField:…

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## [How to broadcast rand(lb:ub)?](https://discourse.julialang.org/t/how-to-broadcast-rand-lb-ub/137546)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 5\
**Last updated:** [June 10, 2026, 7:46pm UTC](https://discourse.julialang.org/t/how-to-broadcast-rand-lb-ub/137546 "2026-06-10T19:46:51Z")

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As from the title, how do I broadcast rand(lowerbound:upperbound) ? e.g. x = \[1,2,3\] a = 2 .\* x .+ rand.() # ok a = @. 2x + rand() # ok a = @. 2x + rand(1:2) # DimensionMismatch error BDW, I am aware of a = 2…

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## [Unexpected path structure for module](https://discourse.julialang.org/t/unexpected-path-structure-for-module/137525)

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**Author:** [@tomtom](https://discourse.julialang.org/u/tomtom)\
**Replies:** 9\
**Last updated:** [June 10, 2026, 11:57am UTC](https://discourse.julialang.org/t/unexpected-path-structure-for-module/137525 "2026-06-10T11:57:38Z")

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I have a long term problem using apropos(): julia\> apropos("interpolate") Base.@async Base.Regex Base.@eval Base.Threads.@spawn DocStringExtensions.Abbreviation DocStringExtensions.interpolation MacroTools.@qq MacroTool…

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## [Juliaup configuration is locked by another process, waiting for it to unlock](https://discourse.julialang.org/t/juliaup-configuration-is-locked-by-another-process-waiting-for-it-to-unlock/121366)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 12\
**Last updated:** [June 10, 2026, 4:42am UTC](https://discourse.julialang.org/t/juliaup-configuration-is-locked-by-another-process-waiting-for-it-to-unlock/121366 "2026-06-10T04:42:54Z")

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Whenever I launch Julia in the bash terminal of VSCode in Ubuntu Linux I get the message: Juliaup configuration is locked by another process, waiting for it to unlock. What could be the reason?

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## [Julia for TechnoEconomic Analyses (TEAs)?](https://discourse.julialang.org/t/julia-for-technoeconomic-analyses-teas/137494)

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**Author:** [@mpampuch](https://discourse.julialang.org/u/mpampuch)\
**Replies:** 3\
**Last updated:** [June 9, 2026, 9:59pm UTC](https://discourse.julialang.org/t/julia-for-technoeconomic-analyses-teas/137494 "2026-06-09T21:59:45Z")

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Hi, I need to perform a Technoeconomic analysis for a technology our group is developing for one of my PhD chapters. I’m new to doing TEAs so I was doing some reading and I came across this blurb in a text book: One w…

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## [How does licensing work for packages that wrap other-licensed binaries?](https://discourse.julialang.org/t/how-does-licensing-work-for-packages-that-wrap-other-licensed-binaries/104350)

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**Author:** [@bilderbuchi](https://discourse.julialang.org/u/bilderbuchi)\
**Replies:** 25\
**Last updated:** [June 9, 2026, 7:12pm UTC](https://discourse.julialang.org/t/how-does-licensing-work-for-packages-that-wrap-other-licensed-binaries/104350 "2026-06-09T19:12:24Z")

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The whole licensing thing is quite gnarly but important, it also affects other packages. For example, Trixi.jl has dependencies that are GPL (not LGPL, p4est and t8code), but claims MIT for itself – how does that work? …

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