usleep under Vax/Ultrix

[Hr Iain Lea]

Just recieved the fuzz and ptyjig test tools from univ. of wisconsin.
Tried compiling them under Ultrix on a vax 8550 but the compiler could
not find the function  usleep().
Checked the man pages but could not find it.
Also did a nm on libc.a and that was negative.
Checked a Vax/BSD machine and that has it.

I thought Ultrix used BSD as its porting base, so what happened ?

Anyway can someone tell me what to use on Ultrix and probably SysV 
in place of  usleep() ?

Thanx

Iain.