---
name: "pvm_probe"
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_probe"
---

# pvm\_probe(3)

Check if message has arrived.

## NAME

pvm\_probe - Check if message has arrived.

## SYNOPSIS

```
C	int bufid = pvm_probe( int tid, int msgtag )
Fortran	call pvmfprobe( tid, msgtag, bufid )
```

## PARAMETERS

- tid

  **Integer task identifier of sending process supplied by the user.**\

- msgtag

  **Integer message tag supplied by the user.** **msgtag should be \>= 0.**\

- bufid

  **Integer returning the value of the new active receive buffer** **identifier.  Values less than zero indicate an error.**

## DESCRIPTION

**The routine** *pvm\_probe* **checks to see if a message with label** *msgtag* **has arrived from** *tid.* **If a matching message has arrived pvm\_probe** **returns a buffer identifier in** *bufid.* **This** *bufid* **can be used with pvm\_bufinfo** **to determine information about the message such as** **its source and length.**

**If the requested message has not arrived, then pvm\_probe** **returns with a 0 in** *bufid.* **If some error occurs** *bufid* **will be \< 0.**

**A -1 in** *msgtag* **or** *tid* **matches anything.** **This allows the user the following options.** **If tid = -1 and msgtag is defined by the user,** **then pvm\_probe will accept a message from any process** **which has a matching msgtag.** **If msgtag = -1 and tid is defined by the user,** **then pvm\_probe will accept any message that is sent from process tid.** **If tid = -1 and msgtag = -1,** **then pvm\_probe will accept any message from any process.**

**pvm\_probe can be called multiple times to check if a given** **message has arrived yet. After the message has arrived,** **pvm\_recv must be called before the message can be unpacked** **into the user's memory using the unpack routines.**

## EXAMPLES

```
C:
	tid = pvm_parent();
	msgtag = 4 ;
	arrived = pvm_probe( tid, msgtag );
	if ( arrived )
		info = pvm_bufinfo( arrived, &len, &tag, &tid );
	else
		/* go do other computing */

Fortran:
	CALL PVMFPROBE( -1, 4, ARRIVED )
	IF ( ARRIVED .GT. 0 ) THEN
		CALL PVMFBUFINFO( ARRIVED, LEN, TAG, TID, INFO )
	ELSE
*		GO DO USEFUL WORK
	ENDIF
```

## ERRORS

**These error conditions can be returned by** *pvm\_probe.*

- PvmBadParam

  **giving an invalid tid value or msgtag.**

- PvmSysErr

  **pvmd not responding.**

## SEE ALSO

**pvm\_bufinfo(3PVM),** **pvm\_getminfo(3PVM),** **pvm\_nrecv(3PVM),** **pvm\_recv(3PVM),** **pvm\_unpack(3PVM)**