How can I pass-through parameters in a powershell function?

Question

I have a function that looks something like this:

function global:Test-Multi {
    Param([string]$Suite)
    & perl -S "$Suite\runall.pl" -procs:$env:NUMBER_OF_PROCESSORS
}

I would like to allow the user to specify more parameters to Test-Multi and pass them directly to the underlying legacy perl script.

Does powershell provide a mechanism to allow additional variadic behavior for this purpose?

score 28 · Accepted Answer · edited Jul 26 '23 at 12:46

28

After seeing your comment, option 3 sounds like exactly what you want.

You have a few options:

Use $args (credit to hjpotter92's answer)
Explicitly define your additional parameters, then parse them all in your function to add them to your perl call.

Use a single parameter with the ValueFromRemainingArguments argument, e.g.

 function global:Test-Multi {
     Param(
         [string]$Suite,
         [parameter(ValueFromRemainingArguments = $true)]
         [string[]]$Passthrough
         )
     & perl -S "$Suite\runall.pl" -procs:$env:NUMBER_OF_PROCESSORS @Passthrough
 }

edited Jul 26 '23 at 12:46

RobH

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answered Nov 13 '15 at 21:27

briantist

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I don't think your "ValueFromRemainingArguments" link goes to the right place.... – Billy ONeal Nov 13 '15 at 21:41
1

@BillyONeal thank you, updated. It's a long-ish document, so `CTRL+F` for `ValueFromRemainingArguments` is recommended. – briantist Nov 13 '15 at 21:43
@BillyONeal nice, I really should have added an example – briantist Nov 13 '15 at 22:04

score 12 · Answer 2 · answered Feb 04 '21 at 16:30

12

$args is not going to pass through arguments correctly. if you want the arguments to remain as separate arguments, you should use @args instead.

answered Feb 04 '21 at 16:30

tiennen07

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1

Huge thanks! It was exactly what I needed. Using `$` formats your arguments as a single string. `@` is the way to go for a proper pass. – Alexandre Daubricourt Oct 14 '21 at 10:36

score 4 · Answer 3 · answered Nov 13 '15 at 21:23

4

I'm not sure about what you wish to achieve, but the arguments passed to a function are accessible in the $args variable available inside the function.

answered Nov 13 '15 at 21:23

hjpotter92

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But $args would contain '-Suite' and its setting as well. I only want to forward arguments my function is not handling. – Billy ONeal Nov 13 '15 at 21:24
@BillyONeal You can filter the `$args` array and remove `-Suite` parameter. – hjpotter92 Nov 13 '15 at 21:26
sure, I can think of ways to do it, but if PS already had a formal way to declare this I wanted to use that. – Billy ONeal Nov 13 '15 at 21:27
To pass the received args to another function, one must use @args and not $args – Tom Jan 26 '22 at 20:14

How can I pass-through parameters in a powershell function?

3 Answers3