CALLBACK:
Factor handbook > C library interface > Passing data between Factor and C > C type specifiers

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Vocabulary
alien.syntax

Syntax
CALLBACK: return type ( parameters )


Inputs and outputs
returna C return type
typea type name
parametersa comma-separated sequence of type/name pairs; type1 arg1, type2 arg2, ...


Word description
Defines a new function pointer C type word type. The newly defined word works both as a C type and as a wrapper for alien-callback for callbacks that accept the given return type and parameters. The ABI of the callback is decided from the ABI of the active LIBRARY: declaration.

Examples
CALLBACK: bool FakeCallback ( int message, void* payload ) : MyFakeCallback ( -- alien ) [| message payload | "message #" write message number>string write " received" write nl t ] FakeCallback ;


Definition