---
name: "MPI_T_cvar_get_num.openmpi"
section: "3"
platform: "linux"
package: "openmpi-doc"
version: "5.0.7-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/MPI_T_cvar_get_num.openmpi"
---

# MPI\_T\_cvar\_get\_num.openmpi(3)

*MPI\_T\_cvar\_get\_num* — Query the number of control variables

## SYNTAX

### C Syntax

```
#include <mpi.h>
int MPI_T_cvar_get_num(int *num_cvar)
```

## OUTPUT PARAMETERS

- •

  **num\_cvar**: Current number of control variables.

## DESCRIPTION

*MPI\_T\_cvar\_get\_num* can be used to query the current number of control variables. The number of control variables may increase throughout the execution of the process but will never decrease.

## ERRORS

*MPI\_T\_cvar\_get\_num* will fail if:

- •

  **MPI\_T\_ERR\_NOT\_INITIALIZED**: The MPI Tools interface not initialized

## COPYRIGHT

2003-2025, The Open MPI Community