---
name: "XMPI_Coloron"
section: "3"
platform: "linux"
package: "lam4-dev"
version: "7.1.4-7.2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/XMPI_Coloron"
---

# XMPI\_Coloron(3)

LAM/MPI-specific function to enable a color in the XMPI trace stream.

## NAME

XMPI\_Coloron -  LAM/MPI-specific function to enable a color in the XMPI trace stream.

## SYNOPSIS

```
#include <mpi.h>
int
XMPI_Coloron(int red, int green, int blue)
```

## INPUT PARAMETER

- **red**

  \- red value (integer)

- **green**

  \- green value (integer)

- **blue**

  \- blue value (integer)

## NOTES

The LAM implementation of MPI is integrated with the XMPI run/debug viewer.  It can generate tracefiles and on-the-fly trace streams suitable for display in XMPI.

A new functionality in XMPI is the ability to enable and disable select colors in the trace stream.  LAM/MPI allows this functionality with the  *XMPI\_Coloron* and  *XMPI\_Coloroff* functions.

*XMPI\_Coloron* is called with  *red* ,  *green* , and  *blue* parameters. Each value may be from 0 to 255.  The resulting RGB composite will become activated for that rank at that point in time.  Enabling and disabling colors is a local action; the calls will return immediately.  The color will be activated or deactivated on the timeline corresponding to the rank that invoked  *XMPI\_Coloron* / *XMPI\_Colorff* in the XMPI trace window.

Only one color is active at a time.  However,  *XMPI\_Coloron* may be invoked multiple times to build a stack of colors.   *XMPI\_Coloroff* will pop the last color off the stack and make the previous color active.

If this function is invoked and tracing is not active, the color is ignored.

There is no profiling version of this function.

This is a LAM/MPI-specific function and is intended mainly for use with XMPI.  If this function is used, it should be used in conjunction with the  *LAM\_MPI* C preprocessor macro

```
#if LAM_MPI
XMPI_Coloron(255, 255, 0);
#endif
```

## NOTES FOR FORTRAN

All MPI routines in Fortran (except for  *MPI\_WTIME* and  *MPI\_WTICK* ) have an additional argument  *ierr* at the end of the argument list. *ierr* is an integer and has the same meaning as the return value of the routine in C.  In Fortran, MPI routines are subroutines, and are invoked with the  *call* statement.

All MPI objects (e.g.,  *MPI\_Datatype* ,  *MPI\_Comm* ) are of type *INTEGER* in Fortran.

## ERRORS

If an error occurs in an MPI function, the current MPI error handler is called to handle it.  By default, this error handler aborts the MPI job.  The error handler may be changed with  *MPI\_Errhandler\_set* ; the predefined error handler  *MPI\_ERRORS\_RETURN* may be used to cause error values to be returned (in C and Fortran; this error handler is less useful in with the C++ MPI bindings.  The predefined error handler  *MPI::ERRORS\_THROW\_EXCEPTIONS* should be used in C++ if the error value needs to be recovered).  Note that MPI does  *not* guarantee that an MPI program can continue past an error.

All MPI routines (except  *MPI\_Wtime* and  *MPI\_Wtick* ) return an error value; C routines as the value of the function and Fortran routines in the last argument.  The C++ bindings for MPI do not return error values; instead, error values are communicated by throwing exceptions of type  *MPI::Exception* (but not by default).  Exceptions are only thrown if the error value is not  *MPI::SUCCESS* .

Note that if the  *MPI::ERRORS\_RETURN* handler is set in C++, while MPI functions will return upon an error, there will be no way to recover what the actual error value was.

- **MPI\_SUCCESS**

  \- No error; MPI routine completed successfully.

- **MPI\_ERR\_ARG**

  \- Invalid argument.  Some argument is invalid and is not identified by a specific error class.  This is typically a NULL pointer or other such error.

- **MPI\_ERR\_INTERN**

  \- An internal error has been detected.  This is fatal.  Please send a bug report to the LAM mailing list (see *http://www.lam-mpi.org/contact.php* ).

## SEE ALSO

XMPI\_Buoy, XMPI\_Coloroff\

## LOCATION

xcoloron.c