mkdir missing from libc.a

[Stephen J. Friedl]

[ discussion on how to get access to SVR3 system calls with an ]
[ old compiler without the latest SVR3 libc.a.                 ]

In article <8057 at mtune.ATT.COM>, jrw at mtune.ATT.COM (Jim Webb) writes:
> If you don't want to trade up to the CPLU4.2 compiler (which *is*
> fantastic, I might add, too) you can access any system call via
> the syscall() routine.

One must be careful with syscall().  Most system calls (open,
read, etc.) are just little wrapper functions in C that set up
the parameters for the GATE assembly instruction, and syscall()
is just a general-purpose interface for it.

Not all system calls, however, are this simple, and you can't
simply vector into the operating system this way.  I don't have
any kind of comprehensive list, but I believe that the entire
signal() family -- one of the improvements with SVR3 -- has
significant extra code that you don't get with syscall().

     Steve

-- 
Stephen J. Friedl / V-Systems, Inc.  /  Santa Ana, CA  / +1 714 545 6442 
3B2-kind-of-guy   / {attmail uunet}!vsi!{bang!}friedl  /  friedl at vsi.com

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