pageout.c

Go to the documentation of this file.

/**
 * \file pageout.c
 *
 * \brief Segment page-out routines.
 *
 * This program is free software under the GNU General Public License
 * (>=v2). Read the file COPYING that comes with GRASS for details.
 *
 * \author GRASS Development Team
 *
 * \date 2005-2009
 */
 
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
 
#include <grass/gis.h>
#include <grass/glocale.h>
 
#include "local_proto.h"
 
/**
 * \brief Internal use only
 *
 * Pages segment to disk.
 *
 * Finds segment value <b>i</b> in segment <b>seg</b> and pages it out
 * to disk.
 *
 * \param[in] SEG segment
 * \param[in] i segment value
 * \return 1 if successful
 * \return -1 on error
 */
int seg_pageout(SEGMENT *SEG, int i)
{
    if (SEG->seek(SEG, SEG->scb[i].n, 0) == -1) {
        int err = errno;
        G_warning(_("File read/write operation failed: %s (%d)"), strerror(err),
                  err);
        return -1;
    }
    errno = 0;
    if (write(SEG->fd, SEG->scb[i].buf, SEG->size) != SEG->size) {
        int err = errno;
 
        if (err)
            G_warning("Segment pageout: %s", strerror(err));
        else
            G_warning("Segment pageout: insufficient disk space?");
        return -1;
    }
    SEG->scb[i].dirty = 0;
 
    return 1;
}