Newsgroup: comp.compilers

arnold@cc.gatech.edu (Arnold Robbins) writes:
>       file a.c:
>               double foo(long a) { return a * 2.0 ; }
>       file b.c
>               extern short foo(double a);
[...]
> Both files will compile just fine.  [...] But when you link the two 
> objects together, the output will be either garbage or a core dump.  
> lint will catch this, the C compiler won't.

There are methods to catch this at link time, with existing linker
technology..  See pp. 122-127 Margaret A. Ellis and Bjarne Stroustrup, 
The Annotated C++ Reference Manual, Addison-Wesley, 1990 and Diomidis 
Spinellis, Type-safe Linkage for Variables and Functions SIGPLAN 
Notices 26(8):74-79, August 1991.

Diomidis
--
Diomidis Spinellis    Internet: <dds@doc.ic.ac.uk>    UUCP: ...!ukc!icdoc!dds
Department of Computing, Imperial College, London SW7
[Good point.  In about 1975, when Dartmouth College wrote their first linker
to go with the PL/I compiler (the other compilers were so fast that it wasn't
worth saving object code, much less linking) and they had a type matching
hack:  The compiler annotated each external definition and reference with
a string of type data, and the linker complained if the type strings weren't
the same.  Simple, fast, and effective.  I presume the C++ approach is
similar, albeit with the type info encoded in the symbol name. -John]
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