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From: rmartin@clear.com (Bob Martin)
Newsgroups: comp.lang.c++
Subject: Re: Unwelcomed Standard Conversion
Message-ID: <1991Apr19.130358.5067@clear.com>
Date: 19 Apr 91 13:03:58 GMT
References: <1991Apr12.153946.21003@urbana.mcd.mot.com>
Organization: Clear Communications, Inc.
Lines: 48

In article <1991Apr12.153946.21003@urbana.mcd.mot.com> qbarnes@urbana.mcd.mot.com (Quentin Barnes) writes:
>I am new to C++ and am puzzled by a standard conversion.  In Lippman
>on p. 160 discussing function matching by standard conversion said
>that any numeric type would match any numeric type.  I thought this to
>be a bad idea and wrote this to test it:
>++
>#include <stream.h>
>
>void ff( short v )
>{
>        cout << "In short ff " << v << "\n";
>}
>
>main()
>{
>        int i = 70000;
>        ff( i );
>}
>++
>This compiled without warnings with both G++ and cfront 2.0 and silently
>truncates the integer.  I could not find anything in Ellis about this.
>It is certainly not "value-preserving".  Bug or feature?

I tried your program and got the same result.  A bit frightening.
Then I tried the following variation:

	#include <iostream.h>

	void ff( short v )
	{
		cout << "In short ff " << v << "\n";
	}

	main()
	{
		long i = 70000;
		ff( i );
	}

This complains (with a warning) about truncating the long.`

I think I am going to avoid int declarations where possible.

-- 
+-Robert C. Martin-----+:RRR:::CCC:M:::::M:| Nobody is responsible for |
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