NAME

indir − indirect system call

ASSEMBLER

(indir = 0.) 
sys indir; call

The system call at the location call is executed.  Execution resumes after the indir call. 

The main purpose of indir is to allow a program to store arguments in system calls and execute them out of line in the data segment.  This preserves the purity of the text segment. 

If indir is executed indirectly, it is a no-op.  If the instruction at the indirect location is not a system call, indir returns error code EINVAL; see intro(2).