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

# MPIL\_Signal(3)

LAM/MPI-specific function to send a LAM signal to a rank in an MPI communicator

## NAME

MPIL\_Signal -  LAM/MPI-specific function to send a LAM signal to a rank in an MPI communicator

## SYNOPSIS

```
#include <mpi.h>
int MPIL_Signal(MPI_Comm comm, int rank, int signo)
```

## INPUT PARAMETERS

- **comm**

  \- MPI communicator (handle)

- **rank**

  \- rank to send it to

- **signo**

  \- signal number

## NOTES

An asynchronous signal is delivered from one process to another with MPIL\_Signal().  The target process is selected with a communicator and a process rank within that communicator.  The remaining argument, signo, identifies the signal to be delivered.  These signals are completely apart from the signals provided by the underlying operating system.  LAM signals, defined in \<lam\_ksignal.h\>, are listed below.

LAM\_SIGTRACE   1    unload trace data\
 LAM\_SIGC       2    user defined\
 LAM\_SIGARECV   3    async receive pending\
 LAM\_SIGUDIE    4    terminate\
 LAM\_SIGARREST  5    suspend execution\
 LAM\_SIGRELEASE 6    continue execution\
 LAM\_SIGA       7    user defined\
 LAM\_SIGB       8    user defined\
 LAM\_SIGFUSE    9    node about to die\
 LAM\_SIGSHRINK  10   another node has died

This is a LAM/MPI-specific function.  Most users should not have use for this function.  If this function is used, it should be used in conjunction with the  *LAM\_MPI* C preprocessor macro

```
#if LAM_MPI
MPIL_Signal(MPI_COMM_WORLD, 0, LAM_SIGUDIE);
#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\_COMM**

  \- Invalid communicator.  A common error is to use a null communicator in a call (not even allowed in  *MPI\_Comm\_rank* ).

- **MPI\_ERR\_RANK**

  \- Invalid source or destination rank.  Ranks must be between zero and the size of the communicator minus one; ranks in a receive ( *MPI\_Recv* ,  *MPI\_Irecv* ,  *MPI\_Sendrecv* , etc.) may also be *MPI\_ANY\_SOURCE* .

- **MPI\_ERR\_OTHER**

  \- Other error; use  *MPI\_Error\_string* to get more information about this error code.

## SEE ALSO

lam\_ksignal\

## LOCATION

mpil\_signal.c