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.TH "MPI_T_PVAR_READRESET" "3" "Jul 06, 2026" "" "Open MPI"
.sp
MPI_T_pvar_readreset — Atomically read and reset the value of a
performance variable
.SH SYNTAX
.SS C Syntax
.INDENT 0.0
.INDENT 3.5
.sp
.EX
#include <mpi.h>

int MPI_T_pvar_readreset(MPI_T_pvar_session session, MPI_T_pvar_handle handle, const void *buf)
.EE
.UNINDENT
.UNINDENT
.SH INPUT PARAMETERS
.INDENT 0.0
.IP \(bu 2
\fBsession\fP: Performance experiment session.
.IP \(bu 2
\fBhandle\fP: Performance variable handle.
.IP \(bu 2
\fBbuf\fP: Initial address of storage location for variable value.
.UNINDENT
.SH DESCRIPTION
.sp
MPI_T_pvar_readreset atomically queries and resets the value of a
performance variable bound to the handle specified by \fIhandle\fP in the
session specified by \fIsession\fP\&. The result is stored in the buffer
pointed to by \fIbuf\fP\&. This function can only be used with performance
variables that are atomic and not readonly. The caller must ensure that
the buffer pointed to by \fIbuf\fP is large enough to hold the entire value
of the performance variable.
.SH ERRORS
.sp
MPI_T_pvar_readreset will fail if:
.INDENT 0.0
.IP \(bu 2
\fBMPI_T_ERR_NOT_INITIALIZED\fP: The MPI Tools interface not initialized
.IP \(bu 2
\fBMPI_T_ERR_INVALID_HANDLE\fP: The handle is invalid or not associated with the session
.IP \(bu 2
\fBMPI_T_ERR_INVALID_SESSION\fP: Session argument is not a valid session
.IP \(bu 2
\fBMPI_T_ERR_PVAR_NO_ATOMIC\fP: Variable cannot be read and written atomically
.IP \(bu 2
\fBMPI_T_ERR_PVAR_NO_WRITE\fP: Variable cannot be reset
.UNINDENT
.sp
\fBSee also:\fP
.INDENT 0.0
.INDENT 3.5
.INDENT 0.0
.IP \(bu 2
MPI_T_pvar_handle_alloc \%<#\:mpi-t-pvar-handle-alloc>
.IP \(bu 2
MPI_T_pvar_get_info \%<#\:mpi-t-pvar-get-info>
.IP \(bu 2
MPI_T_pvar_session_create \%<#\:mpi-t-pvar-session-create>
.IP \(bu 2
MPI_T_pvar_read \%<#\:mpi-t-pvar-read>
.IP \(bu 2
MPI_T_pvar_reset \%<#\:mpi-t-pvar-reset>
.UNINDENT
.UNINDENT
.UNINDENT
.SH Copyright
2003-2026, The Open MPI Community
.\" End of generated man page.