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instance method

MakeMakefile#have_func

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

# File tmp/rubies/ruby-3.0.5/lib/mkmf.rb, line 1080
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

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.

See also #have_framework #have_header #have_devel? #have_library also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.1

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