The syscalls('ON') function establishes the SYSCALL environment. It sets up the REXX predefined variables and blocks all signals. The variable syscall_constants is set to a space-delimited list of all the other predefined variable names. It can be used to expose the variables in a procedure. For example:

procedure expose (syscall_constants)

The function sets this return value:

0

Successful completion.

4

The signal process mask was not set.

7

The process was dubbed, but the SYSCALL environment was not established.

8

The process could not be dubbed.

The following example shows how you can use the syscalls('ON') function at the beginning of a REXX program:

if syscalls('ON')>3 then
   do
   say 'Unable to establish the SYSCALL environment'
   return
   end