Re: strcmp()

[Jon 'maddog' Hall, Executive Director, Linux International]

>Actually I had my original K&R in hand when I answered the question.

Gerry, what was YOUR original K&R may well have been MY second edition.
But then again, we share about the same number of grey hairs.

>Before DEC C was allowed to become the compiler on Digital Unix, it 
>had to successfully compile the entire kernel, libraries and commands.

Right, we were using the portable "C" compiler before that.  And because it
was compiling a BSD kernel, it was obviously "BSD".  QED

DEC "C" was originally built to the ANSI standard, I believe, which caused
all the work that you mentioned to be done, PLUS there are certain issues
in a kernel level compiler and libraries vs a user-level compiler and libraries
that had to be overcome to use DEC "C".

Finally (for those of you not used to this type of trick), the engineers
creating the kernel and the X-server (in particular) knew what type of output
the pcc compiler would generate for certain constructs of "C".  When the
DEC "C" compiler compiled their code and "optimized" it, many times there
was no performance improvement, and often there was a performance penalty.

>Most of the kernel at that time was K&R. Most of libc was ANSI, and the 
>commands were a hodgepodge depending on their origin.

I tend to think of it as "most of the kernel was BSD, all of libc was
BSD, some of which happened to align with ANSI, and the commands were
a hodgepodge, which (by a miracle) happened to link to BSD.

>  But,  strcmp still returned and int back then.

No argument.  It was "always" an int.

> The issues are exactly
> what are  the positive and negative values. ANSI says that strcmp()
> returns greater  than zero, less than zero or zero. Most
> implementations return the  difference between the first non-matching
> characters of the strings. While  optimizing compilers may inline the
> code, the run time libraries frequently  do a simple subtract. 
>  

We are in violent agreement.

md
-- 
=============================================================================
Jon "maddog" Hall
Executive Director, Linux(R) Intern'l    Director of Linux Evangelism         

Linux International                      VA Linux Systems                         
80 Amherst St.                           1382 Bordeaux Ave.
Amherst, N.H. 03031-3032 U.S.A.          Sunnyvale, CA 94089
Internet: [EMAIL PROTECTED]                  [EMAIL PROTECTED]
WWW: http://www.li.org                   WWW: http://www.valinux.com              
Voice: +1.603.672.4557

Board Member: Uniforum Association, USENIX Association

(R)Linux is a registered trademark of Linus Torvalds in several countries.


**********************************************************
To unsubscribe from this list, send mail to
[EMAIL PROTECTED] with the following text in the
*body* (*not* the subject line) of the letter:
unsubscribe gnhlug
**********************************************************