^HF - Host Format

^HF asks the printer to send a stored format back over the link it arrived on, as ZPL text. It is the counterpart to ^DF: one command writes a template into printer memory, and this one reads it out again. The reply shows what a printer holds rather than what the host believes it sent. The command prints nothing, so the renderer has nothing to draw.

Syntax

^HFd:o.x

Support

Recognised, deliberately skippedparsed: none · state: none · rendered: none

Accepted and skipped, because it configures the printer rather than the label. It cannot change the rendered output, and Labelary skips it too.

Returns data over the printer's link rather than changes the label. Both engines ignore it. — not pinned by a test

Labelary renders this command.

Parameters

dStorage deviceoptional · single character

Which memory device to read from.

Default: R:
Invalid value: discarded, and the default applies
Test coverage: The invalid-value rule is not pinned by a test.

oFormat nameoptional · text

Name of the format to send. One to eight alphanumeric characters.

Default: UNKNOWN
Invalid value: discarded, and the default applies
Test coverage: The invalid-value rule is not pinned by a test.

xExtensionoptional · one of a set

Object extension. Always .ZPL for a format.

Default: .ZPL
Invalid value: discarded, and the default applies
Test coverage: No documented value is exercised by a test (.ZPL). The invalid-value rule is not pinned by a test.

.ZPL: The only extension a stored format can have (default)

Behavior

The reply goes to the host, not to the label, and only a listener can read it: a terminal emulator or an open bidirectional connection. A one-way print queue loses the command.

The reply holds the stored ZPL in a rebracketed form rather than verbatim. For a template downloaded as ^XA^DFB:FILE1.ZPL … ^XZ, the guide's own example shows the printer returns ^XA^DFFILE1,, then the stored body, then ^XZ. The device prefix and the extension are gone from the ^DF line, and a comma is there instead. Parse the reply rather than diff it against the request.

The guide holds one inconsistency. Its Format line for this command writes the arguments comma-separated, as ^HFd,o,x, and the example on the same page and Labelary's reference both use the ordinary object path, ^HFR:FILE.ZPL. The object path is the form to write.

The command cannot change the image, so the renderer ignores it and continues with the rest of the format. It reports IGNORED_COMMAND at info severity, which does not reach X-Warnings. Labelary is also silent, so the rendered label is identical in both engines.

Example

Requesting a format alongside an ordinary label. The page renders exactly as it would without the ^HF.

^XA
^HFR:SHIPTO.ZPL
^FO50,50^A0N,40,40^FDPrints as usual^FS
^XZ

Open in viewer

^DF Download FormatStores the rest of the label as a reusable format instead of printing it.
^XF Recall FormatRecalls a stored format and merges the current label's data into it.
^HG Host GraphicUploads a stored graphic back to the host.
^HW Host Directory ListSends a listing of the objects held in printer memory back to the host.