Updated: 2020/Jul/29


__FPTRCAST(3)              Library Functions Manual              __FPTRCAST(3)

NAME
     __FPTRCAST - function pointer cast

SYNOPSIS
     #include <sys/cdefs.h>

     ftype
     __FPTRCAST(ftype, fname);

DESCRIPTION
     The __FPTRCAST() macro can be used to silence warnings produced by
     certain compilers when converting from one function pointer type to
     another.  The ftype argument is the function pointer type to which to
     cast the function pointer in fname.

     This cast should be used sparingly and it is typically used in the
     following situations:
              We know that the function prototypes don't match at all, but we
               don't care because we point it to a function that does not take
               arguments and returns an error.
              We only care about the first few arguments and we don't care
               about the rest.
              We don't care about the return value, we ignore it anyway.

IMPLEMENTATION NOTES
     This macro is implemented by using an intermediate void * cast.

SEE ALSO
     cc(1), cdefs(3)

CAVEATS
     Use of this macro can hide valid errors, and its usage is not recommended
     unless there is a well-thought reason for a cast.  As a general
     guideline, don't use this macro inside other macros because it will hide
     cases where the user of the original macro accidentally used an incorrect
     function pointer.

     Use of this macro is non-portable; this is part of the implementation
     namespace and should only be used in NetBSD code.

NetBSD 9.99                    October 17, 2013                    NetBSD 9.99