Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!oliveb!pyramid!prls!mips!sah
From: sah@mips.COM (Steve Hanson)
Newsgroups: comp.lang.c
Subject: dpANSI Prefined macro names
Message-ID: <2077@gumby.mips.COM>
Date: 25 Apr 88 22:01:15 GMT
Lines: 32
Keywords: machine-dependent,built-in,alloca(3)


	The predefined macro naming convention in dpANSI C appears to
 provide a reasonable way to support machine-dependent functions.

	The MIPS C Compiler use of the stack pointer makes the
*machine-dependent* implementation of alloca(3) impossible.  [The
reasons for this and why we want to support alloca could be the subject
for another posting.] By using the dpANSI C predefined macro naming
convention a built-in function can be provided to *efficiently* support
application packages making use of alloca.

	The idea would be to provide a header file (e.g. alloca.h) 
containing the macro-definition:

	# define alloca(x) _BUILTIN_alloca(x)

The MIPS C Compiler upon seeing the call to _BUILTIN_alloca(x) would 
transform it into the appropriate in-line sequence of code.

Comments regarding experiences with the dpANSI C predefined macro naming
convention and the use of built-in functions are welcome?









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