method

check_signedness

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check_signedness(type, headers = nil, opts = nil, &b) public

Returns the signedness of the given type. You may optionally specify additional headers to search in for the type.

If the type is found and is a numeric type, a macro is passed as a preprocessor constant to the compiler using the type name, in uppercase, prepended with SIGNEDNESS_OF_, followed by the type name, followed by

X where “X” is positive integer if the `type` is unsigned

and a negative integer if the type is signed.

For example, if size_t is defined as unsigned, then check_signedness(‘size_t’) would return +1 and the SIGNEDNESS_OF_SIZE_T=+1 preprocessor macro would be passed to the compiler. The SIGNEDNESS_OF_INT=-1 macro would be set for check_signedness(‘int’)

Show source

# File lib/mkmf.rb, line 1361
  def check_signedness(type, headers = nil, opts = nil, &b)
    typedef, member, prelude = typedef_expr(type, headers)
    signed = nil
    checking_for("signedness of #{type}", STRING_OR_FAILED_FORMAT) do
      signed = try_signedness(typedef, member, [prelude], opts, &b) or next nil
      $defs.push("-DSIGNEDNESS_OF_%s=%+d" % [type.tr_cpp, signed])
      signed < 0 ? "signed" : "unsigned"
    end
    signed
  end

check_signedness

Related methods

X where “X” is positive integer if the type is unsigned

X where “X” is positive integer if the `type` is unsigned