Indirect system call

[Stephen Pope]

In article <28945 at shemp.CS.UCLA.EDU> dieter at lynn.cs.ucla.edu (Dieter Rothmeier) writes:

   While browsing through section 2 of the Unix manual,
   I came upon the concept of an indirect system call,
   as in syscall(2). Now that puzzled me. What might be
   the use for such a facility?

One thing they're good for is to "hide" specific system calls.
For example, one well known symbolic manipulation program
doesn't want you to use it freely, so it hides a call to
"hostid" inside an indirect system call, and compares the
result with that obtained via a normal hostid syscall.

stephen pope
scp at sfi.santafe.edu