The library I use declares a function pointer within a struct's field
named "read" [1]. I think you see where this is going...

    typedef struct ucs_config_parser {
         int (*read) (const char *buf, void *dest,
    const void *arg);
         int (*write)(char *buf, size_t max,
                                           const void *src, const void
    *arg);
         ucs_status_t (*clone)(const void *src, void *dest,
    const void *arg);
         void (*release)(void *ptr, const void *arg);
         void (*help)(char *buf, size_t max, const
    void *arg);
         const void *arg;
    } ucs_config_parser_t;


Since "unistd.h" also declares a "read" function [2], jextract then
(correctly) generates a MethodHandle for it
but uses the wrong FunctionDescriptor belonging to ucx's "read" in the
process.

    static final FunctionDescriptor read$FUNC_ =
    FunctionDescriptor.of(C_INT,
             C_POINTER,
             C_POINTER,
             C_POINTER
    );

    static final MethodHandle read$MH_ = RuntimeHelper.downcallHandle(
             LIBRARIES, "read",
             "(ILjdk/incubator/foreign/MemoryAddress;J)J",
             read$FUNC_, false
    );


As you can see the generated FunctionDescriptor and the descriptor
string ("(ILjdk/incubator/foreign/MemoryAddress;J)J")
do not match. On startup, I immediately get the following Exception
originating from the downcallHandle call.

    Caused by: java.lang.IllegalArgumentException: Carrier size
    mismatch: int != b64[abi/kind=POINTER]