Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!lll-crg!hoptoad!tim
From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.lang.c,comp.unix.wizards
Subject: Re: who called a C routine - get it from the stack frame
Message-ID: <1436@hoptoad.uucp>
Date: Sat, 6-Dec-86 13:25:51 EST
Article-I.D.: hoptoad.1436
Posted: Sat Dec  6 13:25:51 1986
Date-Received: Sun, 7-Dec-86 03:37:27 EST
References: <810@hropus.UUCP> <961@cuuxb.UUCP>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Distribution: comp
Organization: Centram Systems, Berkeley
Lines: 22
Xref: mnetor comp.lang.c:280 comp.unix.wizards:272

There is a portable and clean way to implement a routine finding out the
address of its caller in a few lines of code.  It involves no assembly
language or machine assumptions.  Simply pass the address of the calling
routine as an argument to the routine that needs the address.

foo()
{
	nmuser(foo);
}

nmuser(f)
int (*f)();
{
	/* whatever you are doing using nm */
}

This can be fooled, but an assembly-language caller can easily fool the
other scheme as well by putting a spurious return address on the stack.
-- 
Tim Maroney, Electronic Village Idiot
{ihnp4,sun,well,ptsfa,lll-crg,frog}!hoptoad!tim (uucp)
hoptoad!tim@lll-crg (arpa)