usr/src/usr.lib/libU77/fgetc_.c

/*
char id_fgetc[] = "@(#)fgetc_.c 1.4";
 *
 * get a character from a logical unit bypassing formatted I/O
 *
 * calling sequence:
 *      integer fgetc
 *      ierror = fgetc (unit, char)
 * where:
 *      char will return a character from logical unit
 *      ierror will be 0 if successful; a system error code otherwise.
 */

#include        "../libI77/fiodefs.h"
#include        "../libI77/f_errno.h"

extern unit units[];    /* logical units table from iolib */

long fgetc_(u, c, clen)
long *u; char *c; long clen;
{
        int     i;
        unit    *lu;

        if (*u < 0 || *u >= MXUNIT)
                return((long)(errno=F_ERUNIT));
        lu = &units[*u];
        if (!lu->ufd)
                return((long)(errno=F_ERNOPEN));
        if (lu->uwrt && ! nowreading(lu))
                return((long)errno);
        if ((i = getc (lu->ufd)) < 0)
        {
                if (feof(lu->ufd))
                        return(-1L);
                i = errno;
                clearerr(lu->ufd);
                return((long)i);
        }
        *c = i & 0177;
        return(0L);
}