Method: MakeMakefile#check_signedness

Defined in:
lib/mkmf.rb

#check_signedness(type, headers = nil, opts = nil, &b) ⇒ Object

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')



1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
 
# File 'lib/mkmf.rb', line 1510

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