HEIDENHAIN TNC 407 (243 020) Technical Manual - Manual (Page 594)

01.98
TNC 407/TNC 415/TNC 425 3 Commands 7-133
3.19.3 EXTERN Instruction
For a jump label to be able to access in one file modules which other files have declared as
GLOBAL, it must be declared as EXTERN. The EXTERN instruction must be written at the beginning
of the file.
The commands CM, CMT and CMF can then jump to this label in the program code.
The instructions JP, JPT, JPF, access to a Constants Field and linking with CM to a CASE Branch are
not possible with external jump labels.
The name of the jump label cannot be assigned again in this file for a local jump label. Every external
jump label reduces the number of available local jump labels.
Syntax:
EXTERN
Jump label ;the "Jump Label" Module can now be called from another file
with the CM instruction.