# How to PackageCompile ArgParse

**URL:** <https://discourse.julialang.org/t/how-to-packagecompile-argparse/31994>\
**Category:** New to Julia\
**Created:** [December 8, 2019, 12:54am UTC](https://discourse.julialang.org/t/how-to-packagecompile-argparse/31994 "2019-12-08T00:54:02Z")\
**Posts on this page:** 1\
**Showing post:** 6

<div class="post-metadata">

**Author:** ![mattother](https://avatars.discourse-cdn.com/v4/letter/m/13edae/32.png) [@mattother](https://discourse.julialang.org/u/mattother)\
**Post date:** [August 14, 2020, 12:59pm UTC](https://discourse.julialang.org/t/how-to-packagecompile-argparse/31994/6 "2020-08-14T12:59:28Z")

</div>

I’ve been trying to get the same thing working. I think you’re better off setting it up as a project.

I’m not really sure if this setup is ideal, but it at least works.

First create your project.

```bash
julia -e 'using Pkg; Pkg.generate("MyProj")'
cd MyProj

```

You’ll need to setup a precompile script (see [here](https://julialang.github.io/PackageCompiler.jl/dev/sysimages/#Creating-a-sysimage-using-PackageCompiler-1) for details on precompiling). Unfortunately you can’t really run your main script as your precompile script since ArgParse errors out when passed invalid arguments. So you either need to not run `parse_args` or create some sort of noop command.

So your main app function will look something like this.

/MyProj/src/MyProj.jl

```julia
module MyProj

export run

using ArgParse

function run(parseargs::Bool)
    s = ArgParseSettings()

    @add_arg_table s begin
        "arg1"
            help = "a positional argument"
            required = true
    end

    # don't run parse_args when precompiling.
    # alternatively you could just create a noop command
    # and pass ARGS to the run function.
    if !parseargs
        return
    end

    args = parse_args(ARGS, s)
    println(args)
end

end # module

```

/MyProj/app.jl

```julia
using MyProj
MyProj.run(true)

```

Now you just create the precompile and sysimage creation scripts.

/MyProj/scripts/precompile.js

```julia
using MyProj
MyProj.run(false) # same as app.jl but does not run parse_args()

```

/MyProj/scripts/create\_image.jl

```julia
using PackageCompiler
using Pkg
Pkg.activate(".")
create_sysimage([:ArgParse, :MyProj];
    sysimage_path="MyProj.so",
    precompile_execution_file=joinpath(@ __DIR__ , "precompile.jl")
)

```

Then to setup the sysimage run the script.

```bash
julia scripts/create_image.jl

```

And then you can run your program

```bash
time julia --project=@. -JMyProj.so app.jl arg1 -h

real	0m0.640s
user	0m0.770s
sys 0m0.110s

```

See [here](https://github.com/mattother/argexample) a complete example.

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