.TH MPI_T_cvar_read 3 "11/12/2019" " " "MPI"

.SH NAME

MPI_T_cvar_read \-  Read the value of a control variable 

.SH SYNOPSIS

.nf

int MPI_T_cvar_read(MPI_T_cvar_handle handle, void *buf)

.fi

.SH INPUT PARAMETERS

.PD 0

.TP

.B handle 

- handle to the control variable to be read (handle)

.PD 1

.SH OUTPUT PARAMETERS

.PD 0

.TP

.B buf 

- initial address of storage location for variable value

.PD 1

.SH THREAD AND INTERRUPT SAFETY

This routine is thread-safe.  This means that this routine may be

safely used by multiple threads without the need for any user-provided

thread locks.  However, the routine is not interrupt safe.  Typically,

this is due to the use of memory allocation routines such as 

.I malloc

or other non-MPICH runtime routines that are themselves not interrupt-safe.

.SH ERRORS

All MPI routines (except 

.I MPI_Wtime

and 

.I MPI_Wtick

) return an error value;

C routines as the value of the function and Fortran routines in the last

argument.  Before the value is returned, the current MPI error handler is

called.  By default, this error handler aborts the MPI job.  The error handler

may be changed with 

.I MPI_Comm_set_errhandler

(for communicators),

.I MPI_File_set_errhandler

(for files), and 

.I MPI_Win_set_errhandler

(for

RMA windows).  The MPI-1 routine 

.I MPI_Errhandler_set

may be used but

its use is deprecated.  The predefined error handler

.I MPI_ERRORS_RETURN

may be used to cause error values to be returned.

Note that MPI does 

.B not

guarentee that an MPI program can continue past

an error; however, MPI implementations will attempt to continue whenever

possible.

.PD 0

.TP

.B MPI_SUCCESS 

- No error; MPI routine completed successfully.

.PD 1

.PD 0

.TP

.B MPI_T_ERR_NOT_INITIALIZED 

- The MPI tool information interface is not initialized.

.PD 1

.PD 0

.TP

.B MPI_T_ERR_INVALID_HANDLE 

- The handle is invalid.

.PD 1