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From: rbutterworth@watmath.UUCP (Ray Butterworth)
Newsgroups: comp.lang.c
Subject: Re: Structure type mismatch
Message-ID: <6869@watmath.UUCP>
Date: Sun, 12-Apr-87 13:33:55 EST
Article-I.D.: watmath.6869
Posted: Sun Apr 12 13:33:55 1987
Date-Received: Sat, 18-Apr-87 19:27:36 EST
References: <6821@brl-adm.ARPA>
Organization: U of Waterloo, Ontario
Lines: 35

In article <6821@brl-adm.ARPA>, dsill@NSWC-OAS.arpa writes:
> Try this instead:
> struct { int a,b; } structtype;
> struct structtype foo() { struct structtype c; return c; }

Better yet, try this:
    #include "foo.h"
    FooType foo()
    {
        FooType c;
        return c;
    }
where "foo.h" contains:
    typedef struct {
        int a;
        int b;
    } FooType;
    extern FooType foo();
Then the function that calls foo() can include foo.h too and not
have to define the structure a third time.  It also means that if
you want to add an extra field to the foo structure, you need only
make the change in one very obvous place.  Putting the extern into
the header file means that you don't have to declare the function
in every file that uses it, and that if you should declare it
incorrectly somewhere, the compiler will let you know about it.

Another point of style I've learned to avoid is the use of
commas in declarations.  e.g. instead of "int a,b;" I always
use "int a; int b;".  In the case of int it doesn't really matter,
but if it were "struct foo *a,*b;" and at some time in the future we
decided to get rid of struct foo* and replace it with TypeFooPtr, it
makes it a lot easier when changing the hundreds of declarations of
"struct[  ][  ]*foo[  ]*\*[  ]" to "TypeFooPtr ".  (The brackets
contain blank and tab.)  With the comma list you have to do this
by hand.