---
name: "pvm_setminfo"
section: "3"
platform: "linux"
package: "pvm-dev"
version: "3.4.2-8"
release: "Debian 3.0 (Woody)"
platforms: ["linux"]
url: "https://new.carta.tech/pvm_setminfo"
---

# pvm\_setminfo(3)

Get or set header information of a message.

## NAME

pvm\_getminfo, pvm\_setminfo - Get or set header information of a message.

## SYNOPSIS

```
C	int info = pvm_getminfo( int bufid, struct pvmminfo *mi )
	int info = pvm_setminfo( int bufid, struct pvmminfo *mi )
Fortran	call pvmfgetminfo( bufid, len, ctx, tag, wid, enc, crc,
                           src, dst, info )
	call pvmfsetminfo( bufid, ctx, tag, wid, src, dst, info )
```

## PARAMETERS

- bufid

  **Message buffer identifier.**

- mi

  **Struct containing header information.**

- info

  **Result code.**

**For a description of the Fortran parameters,** **see below.**

## DESCRIPTION

**These functions read and set information passed in message headers,** **which may be of interest to certain applications.** **Typically,** **they will be used when it is necessary to get the message context or** **wait id to use the same values in a reply message.**

**The fields affected are:**

- len

  **The length in bytes of the body of the message.** **This will be equal to the actual size of the data packed,** **if** *PvmDataRaw* is used, otherwise it may include pad bytes.

- ctx

  The context sent with the message.

- tag

  The tag sent with the message.

- wid

  Wait Identifier, used to match a reply message to the corresponding request.

- enc

  Message Encoding, either the *data signature* of the sender, or 0x10000000 for XDR.

- crc

  The CRC checksum of the message body.

- src

  The tid of the sender.

- dst

  The tid of the destination.

All fields may be read, but only *ctx*, *tag*, *wid*, *src* and *dst* may be set.

pvm\_getmwid and pvm\_setmwid return PvmOk if successful, or else a negative error code.

## EXAMPLES

```
	/* return a message to a caller with the same tag and wait id */
	struct pvmminfo mi1, mi2;
	pvm_recv(-1, -1);
	/* ... process, compose reply message */
	pvm_getminfo(pvm_getrbuf(), &mi1);
	pvm_getminfo(pvm_getsbuf(), &mi2);
	mi2.wid = mi1.wid;
	pvm_send(mi1.src, mi1.tag);
```

## ERRORS

The following error conditions can be returned by pvm\_getmwid or pvm\_setmwid:

- PvmBadParam

  Invalid value for *bufid* or *mi* argument.

- PvmNoSuchBuf

  Message buffer *bufid* doesn't exist.

## SEE ALSO

pvm\_bufinfo(3PVM)