# MX\_SETERSATZ

> [HTML Version](mx_setersatz.htm)

_Added February 2026_

**xcall MIAMEX, MX\_SETERSATZ, erzdef \{, status\}**

MX\_SETERSATZ (208) allows for adding or updating ERSATZ device definitions without relaunching session. This may be useful in applications where the specific location of certain system-wide ersatz devices (e.g. REPORTS:) may need to change based on the user, menu selection, etc.

**Parameters**

_erzdef  _([String](string.md))  \[in\] 

either a filespec containing ERSATZ definitions, or a single ersatz definition in the format: erznam:=device:\{\[p,pn\]\}

_status_  ([Num](num.md))  \[out\] 

optionally returns status of operation:

| **Value** | **Meaning** |
|------|------|
| 0 | single definition replaced |
| 1 | definition(s) added |
| \-1 | invalid format |
| \-2 | exceeded max # of allowed ERSATZ definitions |
| \-3 | file not found |


**See Also**

•	[ERSATZ.LIT](ersatz_lit.md)

**History**

2026 February, A-Shell 7.0.1783:  Routine added to A-Shell.