Method: MakeMakefile#have_func

Defined in:
lib/mkmf.rb

#have_func(func, headers = nil, opt = "", &b) ⇒ Object

Returns whether or not the function func can be found in the common header files, or within any headers that you provide. If found, a macro is passed as a preprocessor constant to the compiler using the function name, in uppercase, prepended with HAVE_.

To check functions in an additional library, you need to check that library first using have_library(). The func shall be either mere function name or function name with arguments.

For example, if have_func('foo') returned true, then the HAVE_FOO preprocessor macro would be passed to the compiler.



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# File 'lib/mkmf.rb', line 1081

def have_func(func, headers = nil, opt = "", &b)
  checking_for checking_message(func.funcall_style, headers, opt) do
    if try_func(func, $libs, headers, opt, &b)
      $defs << "-DHAVE_#{func.sans_arguments.tr_cpp}"
      true
    else
      false
    end
  end
end