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From: bill@twwells.uucp (T. William Wells)
Newsgroups: comp.lang.c
Subject: Re: Calling multiple functions in a macro.
Message-ID: <139@twwells.uucp>
Date: 2 Nov 88 01:12:52 GMT
References: <353@marob.MASA.COM>
Reply-To: bill@twwells.UUCP (T. William Wells)
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In article <353@marob.MASA.COM> daveh@marob.masa.com (Dave Hammond) writes:
: In attempting to construct a macro which calls several functions,
: but can be used as a single statement (i.e. without braces in an if/else
: construct), I can see 2 possible alternatives:
:
: 1.
: #define FOO() do { foo1(); foo2(); foo3() foo4(); } while(0)
:
: 2.
: #define FOO() foo1(), foo2(), foo3(), foo4()
:
: The first adds quite a bit of code to the program and makes lint
: complain about constants in conditional text.

The first is unlikely to add that much to the code. Go look at the
assembly output.

: The second compiles, executes and lints correctly (on Xenix), but
: is it portable to string function calls in this manner?

Yes it is portable. But save yourself some headaches and write it:

#define FOO() (foo1(), foo2(), foo3(), foo4())

The extra parentheses can prevent problems with, e.g.:

	a + FOO()

which would otherwise add a to the result of foo1 and toss the
result, when what you want it to do is add it to foo4 and return the
result.

---
Bill
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