public sealed interface FunctionDescriptor
FunctionDescriptor is a preview API of the Java platform.
Preview features may be removed in a future release, or upgraded to permanent features of the Java platform.
A function descriptor models the signature of a foreign function. A function descriptor is made up of zero or more
 argument layouts, and zero or one return layout. A function descriptor is used to create
 downcall method handlesPREVIEW and
 upcall stubsPREVIEW.
- Implementation Requirements:
- Implementing classes are immutable, thread-safe and value-based.
- Since:
- 19
- See Also:
- 
Method SummaryModifier and TypeMethodDescriptionappendArgumentLayouts(MemoryLayoutPREVIEW... addedLayouts) Returns a function descriptor with the given argument layouts appended to the argument layouts of this function descriptor.Returns the argument layouts of this function descriptor (as an unmodifiable list).changeReturnLayout(MemoryLayoutPREVIEW newReturn) Returns a function descriptor with the provided return layout.Returns a new function descriptor, with no return layout.insertArgumentLayouts(int index, MemoryLayoutPREVIEW... addedLayouts) Returns a function descriptor with the given argument layouts inserted at the given index, into the argument layout array of this function descriptor.static FunctionDescriptorPREVIEWof(MemoryLayoutPREVIEW resLayout, MemoryLayoutPREVIEW... argLayouts) Creates a function descriptor with the given return and argument layouts.static FunctionDescriptorPREVIEWofVoid(MemoryLayoutPREVIEW... argLayouts) Creates a function descriptor with the given argument layouts and no return layout.Returns the return layout (if any) of this function descriptor.Returns the method type consisting of the carrier types of the layouts in this function descriptor.
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Method Details- 
returnLayoutOptional<MemoryLayoutPREVIEW> returnLayout()Returns the return layout (if any) of this function descriptor.- Returns:
- the return layout (if any) of this function descriptor
 
- 
argumentLayoutsList<MemoryLayoutPREVIEW> argumentLayouts()Returns the argument layouts of this function descriptor (as an unmodifiable list)..- Returns:
- the argument layouts of this function descriptor (as an unmodifiable list)
 
- 
appendArgumentLayoutsReturns a function descriptor with the given argument layouts appended to the argument layouts of this function descriptor.- Parameters:
- addedLayouts- the argument layouts to append.
- Returns:
- a new function descriptor, with the provided additional argument layouts.
- Throws:
- IllegalArgumentException- if one of the layouts in- addedLayoutsis a padding layout.
 
- 
insertArgumentLayoutsReturns a function descriptor with the given argument layouts inserted at the given index, into the argument layout array of this function descriptor.- Parameters:
- index- the index at which to insert the arguments
- addedLayouts- the argument layouts to insert at given index.
- Returns:
- a new function descriptor, with the provided additional argument layouts.
- Throws:
- IllegalArgumentException- if one of the layouts in- addedLayoutsis a padding layout.
- IllegalArgumentException- if- index < 0 || index > argumentLayouts().size().
 
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changeReturnLayoutReturns a function descriptor with the provided return layout.- Parameters:
- newReturn- the new return layout.
- Returns:
- a new function descriptor, with the provided return layout.
- Throws:
- IllegalArgumentException- if- newReturnis a padding layout.
 
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dropReturnLayoutFunctionDescriptorPREVIEW dropReturnLayout()Returns a new function descriptor, with no return layout.- Returns:
- a new function descriptor, with no return layout
 
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toMethodTypeMethodType toMethodType()Returns the method type consisting of the carrier types of the layouts in this function descriptor.The carrier type of a layout Lis determined as follows:- If Lis aValueLayoutPREVIEW the carrier type is determined throughValueLayout.carrier()PREVIEW.
- If Lis aGroupLayoutPREVIEW or aSequenceLayoutPREVIEW, the carrier type isMemorySegmentPREVIEW.
 - API Note:
- A function descriptor cannot, by construction, contain any padding layouts. As such, it is not necessary to specify how padding layout should be mapped to carrier types.
- Returns:
- the method type consisting of the carrier types of the layouts in this function descriptor.
 
- If 
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ofstatic FunctionDescriptorPREVIEW of(MemoryLayoutPREVIEW resLayout, MemoryLayoutPREVIEW... argLayouts) Creates a function descriptor with the given return and argument layouts.- Parameters:
- resLayout- the return layout.
- argLayouts- the argument layouts.
- Returns:
- a new function descriptor with the provided return and argument layouts.
- Throws:
- IllegalArgumentException- if- resLayoutis a padding layout.
- IllegalArgumentException- if one of the layouts in- argLayoutsis a padding layout.
 
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ofVoidCreates a function descriptor with the given argument layouts and no return layout. This is useful to model functions that return no values.- Parameters:
- argLayouts- the argument layouts.
- Returns:
- a new function descriptor with the provided argument layouts.
- Throws:
- IllegalArgumentException- if one of the layouts in- argLayoutsis a padding layout.
 
 
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FunctionDescriptorwhen preview features are enabled.