[Proj] Modern C functions

Gerald I. Evenden geraldi.evenden at gmail.com
Fri Feb 27 10:19:44 EST 2009

On Thursday 26 February 2009 10:31:58 pm Glynn Clements wrote:
> Gerald I. Evenden wrote:
> > This is a quick probe of the programming types in this group.
> >
> > In finalizing Rel. 2.0 of geodesic and libgeodesy I ran across functions
> > under the <string.h> heading which are not in the typical (read Harrison
> > & Steele) library references: strcasecmp and strncasecmp.  These are
> > noted in the Gnu man.3 as Posix 2001 standard routines.  Obviously, these
> > two routines replace strcmp and strncmp and make comparisons case
> > independent.
> >
> > As soon as I became aware of them I have included them to eliminate the
> > nasty, nasty fact of having to shift when typing in WGS84 and can now use
> > ellps=wgs84.
> >
> > A little net browsing has yielded mixed results as to how well know these
> > functions are.
> >
> > Thus my question here is: do non-Gnu C compilers used by this audience
> > recognize these functions?
> It's not an issue for the compiler, but for the standard library.

IMHO, when discussing in a general context, the term "compiler" consists of 
the entire process of generating an executable module and all it constituent 
pieces.  Including libraries.

> The are specified by POSIX, but not by ANSI C (neither C89 nor C99).

I have not concerned myself with "ANSI" in 15+ years as it seems superfluous 
with so many other "standards" around.

> As others have already pointed out, Windows doesn't provide them.
> Also, gcc won't recognise them if you use -ansi and don't explicitly
> add the POSIX feature macros, e.g. -D_POSIX_SOURCE. I don't know
> whether uclibc has them.

The term "uclibc" does not make sense to me.  I am only used to the 
terminology libxxxxx.  The "uc" prefix seems odd.

As for Windoze, I understand that there are non-M$ compilers available for 
Windoze and these may not be so self righteous.

> Also, bear in mind that the behaviour depends upon the locale; using
> them for strings containing anything other than alphanumeric
> characters is problematic.

Seemingly the most common usage is for equality: strXcmp(a,b)==0.  I see no 
hassle with testing anything within the character set as long as str a and 
str b are of the  same character set type.  But yes, there may be some 
problems with some non-Latin alphabetics.  However, in the context of a given 
program and its control of the alphabet---like geodesic, proj, etc.---then we 
are only testing against an in-house alphabet.  If someone wants to convert a 
program into using a non-latin alphabet, then the problem is transferred to 
their domain.

The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist

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