int QSget_solution (QSprob p, double *value, double *x, double *pi,
    double *slack, double *rc)

This function allows the user to obtain different components of the solution in one call (if some component is not needed, the field can be given as NULL). To obtain individual components, it is easier to use the specialized functions listed in the Accessing an LP Solution section in the Callable Function List.

/* p is an initialized QSprob, a handle to an existing LP problem  */
/* Assume that p was solved with QSopt_dual() or QSopt_primal, and */
/* that the status code indicates that an optimal solution was     */
/* obtained.  We will grab and print all solution components.      */

int rval, ncols, nrows, i, j;
double value;
double *x, *pi, *slack, *rc;
char **colnames, **rownames;

ncols = QSget_colcount (p);
nrows = QSget_rowcount (p);

/* Get the variable names and the constraint names, for printing */

colnames = (char **) malloc (ncols * sizeof (char *));
rownames = (char **) malloc (nrows * sizeof (char *));
rval = QSget_colnames (p, colnames);
if (rval) {
    fprintf (stderr, 
             "Could not get column names, error code %d\n", rval);
    /* free the memory for colnames and rownames                 */
    /* return an error code                                      */
}
rval = QSget_rownames (p, rownames);
if (rval) {
    fprintf (stderr, 
             "Could not get row names, error code %d\n", rval);
    /* free the memory for colnames and rownames                 */
    /* return an error code                                      */
}

/* Allocate memory for the solution components.                  */

x  = (double *) malloc (ncols * sizeof (double));
rc = (double *) malloc (ncols * sizeof (double));
pi = (double *) malloc (nrows * sizeof (double));
slack = (double *) malloc (nrows * sizeof (double));

rval = QSget_solution (p, &value, x, pi, slack, rc);
if (rval) {
    fprintf (stderr, 
             "Could not get solution, error code %d\n", rval);
    /* free the memory for x, rc, pi, slack, colnames, rownames  */
    /* return an error code                                      */
}

printf ("Objective Value = %.6f\n", value);
for (j = 0; j < ncols; j++) {
    printf ("%s = %.6f, reduced cost = %.6f\n", 
            colnames[j], x[j], rc[j]);
}
for (i = 0; i < nrows; i++) {
    printf ("dual %s = %.6f, slack = %.6f\n", 
            rownames[i], pi[i], slack[i]);
}

/* Free the memory, including the individual names of cols and rows */

free (x);  free (rc);  free (pi);  free (slack);
for (j = 0; j < ncols; j++) {
    /* Use QSfree for memory from QSopt functs  */
    QSfree (colnames[j]);
}
free (colnames);
for (i = 0; i < nrows; i++) {
    /* Use QSfree for memory from QSopt functs  */
    QSfree (rownames[i]);   
}
free (rownames);