A zcentry specifies the characteristics of the external routine. It associates each routine name with an actual routine, and specifies data types and argument-passing mechanisms for the parameters passed to or from each routine. A zcentry contains four types of lines.

The format for a zcentry is:

	[package]
	routine
	[return]
	[input] ...
	[output] ...
	

The information for each external call table entry MUST appear in the order shown above.

Example:

	.library "gtm$dist:gtmzcall.mlb" 
	zcinit
	routinecallname=lexp, linkname=l1, inputs=1,outputs=1
	returnclass=status
	inputposition=1, mechanism=descriptor, type=string
	outputposition=2, mechanism=reference, type=long

	package my_package
	routinecallname=trans, linkname=trns, inputs=1,outputs=1
	returnclass=value, type=double
	inputposition=1, mechanism=reference, type=string
	outputposition=2, mechanism=descriptor, type=quad
	zcallfin
	.end	
	

Each of the segments starting with the routine line and ending with the output line forms a zcentry. Zcentries and the package line are explained below.