A tale of two C's.

[Doug Gwyn]

In article <154 at ghostwheel.UUCP> ned at ghostwheel.aca.mcc.com.UUCP (Ned Nowotny) writes:
>When portability is not an issue, a programmer should be free to use
>his or her own implementation of a standard library function.

I think you need to explain why this is considered desirable.

Many of the library functions are likely to have secret internal
interfaces to others, so you cannot implement them correctly in a
portable application.  Others, such as strcpy(), will be implemented
more efficiently in general in the standard library than in your
application.  If you try to speed them up by providing subset
functionality, you may break other library routines that need to use
these with full functionality.

Whenever the C library is inappropriate, you should code for the
"freestanding" environment rather than the "hosted" environment.
Then you can define almost all functions as you see fit without
breaking anything.  Of course you may wish to steal some functions
from the hosted-environment library, but whether or not that will
work depends on details of the specific implementation, among other
things.