Passing variadic C args through?

I've had a long-working `debugLog()` method that looks like this:

func
debugLog<T>(_ inMsg: T, file inFile : String = #file, line inLine : Int = #line)
{
	let file = (inFile as NSString).lastPathComponent
	let s = "\(file):\(inLine)    \(inMsg)"
	print(s)
}

I wanted to add a version that works like `String(format:)`:

func
debugLog(format inFormat: String, file inFile : String = #file, line inLine : Int = #line, _ inArgs: CVarArg...)
{
	let s = String(format: inFormat, inArgs)
	debugLog(s, file: inFile, line: inLine)
}

While this compiles and executes, all of the values are zero for this example:

let xc = CGFloat(1.0)
let yc = CGFloat(0.0)
let len = CGFloat(282.1364917907643)

debugLog(format: "Pixel %f, %f length too far %f", xc, yc, len)

Output:

FisheyeImageRenderer.swift:108    Pixel 0.000000, 0.000000 length too far 0.000000

Something is being misinterpreted in the passing of `inArgs: CVarArg...`

TIA,

···

--
Rick Mann
rmann@latencyzero.com

Heh, it would be nice to catch this. You're collecting a bunch of arguments in an Array, and then passing that array straight on as a single argument itself, which means it gets passed as either an NSArray or a pointer (not sure which). Use 'init(format:arguments:)' instead.

Jordan

···

On Nov 14, 2017, at 17:19, Rick Mann via swift-users <swift-users@swift.org> wrote:

I've had a long-working `debugLog()` method that looks like this:

func
debugLog<T>(_ inMsg: T, file inFile : String = #file, line inLine : Int = #line)
{
	let file = (inFile as NSString).lastPathComponent
	let s = "\(file):\(inLine)    \(inMsg)"
	print(s)
}

I wanted to add a version that works like `String(format:)`:

func
debugLog(format inFormat: String, file inFile : String = #file, line inLine : Int = #line, _ inArgs: CVarArg...)
{
	let s = String(format: inFormat, inArgs)
	debugLog(s, file: inFile, line: inLine)
}

While this compiles and executes, all of the values are zero for this example:

let xc = CGFloat(1.0)
let yc = CGFloat(0.0)
let len = CGFloat(282.1364917907643)

debugLog(format: "Pixel %f, %f length too far %f", xc, yc, len)

Output:

FisheyeImageRenderer.swift:108    Pixel 0.000000, 0.000000 length too far 0.000000

Something is being misinterpreted in the passing of `inArgs: CVarArg...`

TIA,

--
Rick Mann
rmann@latencyzero.com

_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users

I tried to find an alternative init() to use, but couldn't (despite dozens of releases, Xcode's code completion still fails much of the time). Thanks for pointing me to the right one!

Should I file a bug?

···

On Nov 14, 2017, at 17:47 , Jordan Rose <jordan_rose@apple.com> wrote:

Heh, it would be nice to catch this. You're collecting a bunch of arguments in an Array, and then passing that array straight on as a single argument itself, which means it gets passed as either an NSArray or a pointer (not sure which). Use 'init(format:arguments:)' instead.

Jordan

On Nov 14, 2017, at 17:19, Rick Mann via swift-users <swift-users@swift.org> wrote:

I've had a long-working `debugLog()` method that looks like this:

func
debugLog<T>(_ inMsg: T, file inFile : String = #file, line inLine : Int = #line)
{
	let file = (inFile as NSString).lastPathComponent
	let s = "\(file):\(inLine)    \(inMsg)"
	print(s)
}

I wanted to add a version that works like `String(format:)`:

func
debugLog(format inFormat: String, file inFile : String = #file, line inLine : Int = #line, _ inArgs: CVarArg...)
{
	let s = String(format: inFormat, inArgs)
	debugLog(s, file: inFile, line: inLine)
}

While this compiles and executes, all of the values are zero for this example:

let xc = CGFloat(1.0)
let yc = CGFloat(0.0)
let len = CGFloat(282.1364917907643)

debugLog(format: "Pixel %f, %f length too far %f", xc, yc, len)

Output:

FisheyeImageRenderer.swift:108    Pixel 0.000000, 0.000000 length too far 0.000000

Something is being misinterpreted in the passing of `inArgs: CVarArg...`

TIA,

--
Rick Mann
rmann@latencyzero.com

_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users

--
Rick Mann
rmann@latencyzero.com

Sure. I'm not sure we have a good idea for how to catch the bug—what if you really meant to pass the array as an NSArray?—but it's worth recording somewhere. Thanks, Rick.

Jordan

···

On Nov 14, 2017, at 18:00, Rick Mann <rmann@latencyzero.com> wrote:

I tried to find an alternative init() to use, but couldn't (despite dozens of releases, Xcode's code completion still fails much of the time). Thanks for pointing me to the right one!

Should I file a bug?

On Nov 14, 2017, at 17:47 , Jordan Rose <jordan_rose@apple.com> wrote:

Heh, it would be nice to catch this. You're collecting a bunch of arguments in an Array, and then passing that array straight on as a single argument itself, which means it gets passed as either an NSArray or a pointer (not sure which). Use 'init(format:arguments:)' instead.

Jordan

On Nov 14, 2017, at 17:19, Rick Mann via swift-users <swift-users@swift.org> wrote:

I've had a long-working `debugLog()` method that looks like this:

func
debugLog<T>(_ inMsg: T, file inFile : String = #file, line inLine : Int = #line)
{
	let file = (inFile as NSString).lastPathComponent
	let s = "\(file):\(inLine)    \(inMsg)"
	print(s)
}

I wanted to add a version that works like `String(format:)`:

func
debugLog(format inFormat: String, file inFile : String = #file, line inLine : Int = #line, _ inArgs: CVarArg...)
{
	let s = String(format: inFormat, inArgs)
	debugLog(s, file: inFile, line: inLine)
}

While this compiles and executes, all of the values are zero for this example:

let xc = CGFloat(1.0)
let yc = CGFloat(0.0)
let len = CGFloat(282.1364917907643)

debugLog(format: "Pixel %f, %f length too far %f", xc, yc, len)

Output:

FisheyeImageRenderer.swift:108    Pixel 0.000000, 0.000000 length too far 0.000000

Something is being misinterpreted in the passing of `inArgs: CVarArg...`

TIA,

--
Rick Mann
rmann@latencyzero.com

_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users

--
Rick Mann
rmann@latencyzero.com

Here you go: https://bugs.swift.org/browse/SR-6386

···

On Nov 14, 2017, at 18:01 , Jordan Rose <jordan_rose@apple.com> wrote:

Sure. I'm not sure we have a good idea for how to catch the bug—what if you really meant to pass the array as an NSArray?—but it's worth recording somewhere. Thanks, Rick.

Jordan

On Nov 14, 2017, at 18:00, Rick Mann <rmann@latencyzero.com> wrote:

I tried to find an alternative init() to use, but couldn't (despite dozens of releases, Xcode's code completion still fails much of the time). Thanks for pointing me to the right one!

Should I file a bug?

On Nov 14, 2017, at 17:47 , Jordan Rose <jordan_rose@apple.com> wrote:

Heh, it would be nice to catch this. You're collecting a bunch of arguments in an Array, and then passing that array straight on as a single argument itself, which means it gets passed as either an NSArray or a pointer (not sure which). Use 'init(format:arguments:)' instead.

Jordan

On Nov 14, 2017, at 17:19, Rick Mann via swift-users <swift-users@swift.org> wrote:

I've had a long-working `debugLog()` method that looks like this:

func
debugLog<T>(_ inMsg: T, file inFile : String = #file, line inLine : Int = #line)
{
	let file = (inFile as NSString).lastPathComponent
	let s = "\(file):\(inLine)    \(inMsg)"
	print(s)
}

I wanted to add a version that works like `String(format:)`:

func
debugLog(format inFormat: String, file inFile : String = #file, line inLine : Int = #line, _ inArgs: CVarArg...)
{
	let s = String(format: inFormat, inArgs)
	debugLog(s, file: inFile, line: inLine)
}

While this compiles and executes, all of the values are zero for this example:

let xc = CGFloat(1.0)
let yc = CGFloat(0.0)
let len = CGFloat(282.1364917907643)

debugLog(format: "Pixel %f, %f length too far %f", xc, yc, len)

Output:

FisheyeImageRenderer.swift:108    Pixel 0.000000, 0.000000 length too far 0.000000

Something is being misinterpreted in the passing of `inArgs: CVarArg...`

TIA,

--
Rick Mann
rmann@latencyzero.com

_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users

--
Rick Mann
rmann@latencyzero.com

--
Rick Mann
rmann@latencyzero.com