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/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
* Copyright (C) 1997 University of Chicago.
* See COPYRIGHT notice in top-level directory.
*/
#include "adio.h"
/* returns the current location of the shared_fp in terms of the
no. of etypes relative to the current view, and also increments the
shared_fp by the number of etypes to be accessed (incr) in the read
or write following this function. */
void ADIOI_NFS_Get_shared_fp(ADIO_File fd, ADIO_Offset incr, ADIO_Offset *shared_fp,
int *error_code);
void ADIO_Get_shared_fp(ADIO_File fd, ADIO_Offset incr, ADIO_Offset *shared_fp,
int *error_code)
{
ADIO_Status status;
ADIO_Offset new_fp;
MPI_Comm dupcommself;
/* Set the shared_fp in case this comes from an uninitialized stack variable
The read routines will not read into the address of this variable if the file
size of a shared pointer is 0, and if incr is always zero, this value will remain
uninitialized. Initialize it here to prevent incorrect values
*/
*shared_fp = 0;
#ifdef ROMIO_NFS
if (fd->file_system == ADIO_NFS) {
ADIOI_NFS_Get_shared_fp(fd, incr, shared_fp, error_code);
return;
}
#endif
if (fd->shared_fp_fd == ADIO_FILE_NULL) {
MPI_Comm_dup(MPI_COMM_SELF, &dupcommself);
fd->shared_fp_fd = ADIO_Open(MPI_COMM_SELF, dupcommself,
fd->shared_fp_fname,
fd->file_system,
fd->fns,
ADIO_CREATE | ADIO_RDWR | ADIO_DELETE_ON_CLOSE,
0, MPI_BYTE, MPI_BYTE,
MPI_INFO_NULL,
ADIO_PERM_NULL, error_code);
if (*error_code != MPI_SUCCESS) return;
ADIOI_WRITE_LOCK(fd->shared_fp_fd, 0, SEEK_SET, sizeof(ADIO_Offset));
ADIO_ReadContig(fd->shared_fp_fd, shared_fp, sizeof(ADIO_Offset),
MPI_BYTE, ADIO_EXPLICIT_OFFSET, 0, &status, error_code);
/* if the file is empty, the above function may return error
(reading beyond end of file). In that case, shared_fp = 0,
set above, is the correct value. */
}
else {
ADIOI_WRITE_LOCK(fd->shared_fp_fd, 0, SEEK_SET, sizeof(ADIO_Offset));
ADIO_ReadContig(fd->shared_fp_fd, shared_fp, sizeof(ADIO_Offset),
MPI_BYTE, ADIO_EXPLICIT_OFFSET, 0, &status, error_code);
if (*error_code != MPI_SUCCESS) {
ADIOI_UNLOCK(fd->shared_fp_fd, 0, SEEK_SET, sizeof(ADIO_Offset));
return;
}
}
if (incr == 0) {goto done;}
new_fp = *shared_fp + incr;
ADIO_WriteContig(fd->shared_fp_fd, &new_fp, sizeof(ADIO_Offset),
MPI_BYTE, ADIO_EXPLICIT_OFFSET, 0, &status, error_code);
done:
ADIOI_UNLOCK(fd->shared_fp_fd, 0, SEEK_SET, sizeof(ADIO_Offset));
}
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