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I’m working with Metal on iPad Playgrounds and made a simple editor to help craft shaders. Press a button, it tries to make the library, and reports any errors or warnings. The problem is it doesn’t report warnings if the compile was successful.
I’m using the version of makeLibrary with a completion handler which passes in both a MTLLibrary? and Error? because the docs specifically say “Both library and error can be non-nil if the compiler successfully generates a library with warnings.” However I’m not seeing that happen, when there’s only warnings the Error parameter is nil.
Maybe I’m misunderstanding or using something wrong. Is this a bug or how do I get the warnings on a successful compile?
Here’s a demo. It should show 2 warnings but doesn’t because err is nil. Add an extraneous character in source to cause an error and then err is not nil and shows the 2 warnings.
import SwiftUI
let source = """
#include <metal_stdlib>
using namespace metal;
float something() {}
#warning "foo";
"""
struct ContentView: View {
var body: some View {
Button("test") {
guard let device = MTLCreateSystemDefaultDevice() else { return }
device.makeLibrary(source: source, options: nil) { lib, err in
if err == nil {
print("no errors or warnings")
} else if let err = err as? MTLLibraryError {
print("found errors or warnings")
print(err.localizedDescription)
} else {
print("unknown error type")
}
}
}
}
}
Oh, and this is where it says both library and error can be non-nil
https://developer.apple.com/documentation/metal/mtlnewlibrarycompletionhandler
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VectorMonkey.
Last updated
VectorMonkey.
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