DIAL(3C) DOMAIN/IX Reference Manual (SYS5) DIAL(3C)
NAME
dial - establish an outgoing terminal line connection
USAGE
#include <dial.h>
int dial (call)
CALL call;
void undial (fd)
int fd;
DESCRIPTION
Dial returns a file descriptor for a terminal line that is
open for reading and writing. The argument to dial is a
CALL structure (defined in the <dial.h> header file).
When finished with the terminal line, the calling program
must invoke undial to release the semaphore that was set
during the allocation of the terminal device.
The definition of CALL in the <dial.h> header file is:
typedef struct {
struct termio *attr; /* pointer to termio attribute struct */
int baud; /* transmission data rate */
int speed; /* 212A modem: low=300, high=1200 */
char *line; /* device name for out-going line */
char *telno; /* pointer to tel-no digits string */
int modem; /* specify modem control for direct lines */
char *device; /*Will hold the name of the device used
to make a connection */
int dev_len; /* The length of the device used to
make connection */
} CALL;
The CALL element speed is intended only for use with an out-
going dialed call, in which case it should be set to either
300 or 1200 to identify the 113A modem, or the high- or
low-speed setting on the 212A modem. Note that the 113A
modem or the low-speed setting of the 212A modem will
transmit at any rate between 0 and 300 bits per second.
However, the high-speed setting of the 212A modem transmits
and receives at 1200 bits per second only. The CALL element
baud sets the transmission baud rate. For example, you can
set baud to 110 and speed to 300 (or 1200). However, if you
set speed to 1200, you must set baud to high (1200).
If the terminal line is a direct line, you must place a
string pointer to the device-name in the line element in the
CALL structure. Legal values for such terminal device names
are kept in the L-devices file. In this case, the value of
Printed 5/10/85 DIAL-1
DIAL(3C) DOMAIN/IX Reference Manual (SYS5) DIAL(3C)
the baud element, will be determined by the L-devices file,
if the element is initialized to -1 in the CALL structure.
The telno element is for a pointer to a character string
representing the telephone number to be dialed. The termi-
nation symbol will be supplied by the dial function, and
should not be included in the telno string passed to dial in
the CALL structure.
Use the CALL element modem to specify modem control for
direct lines. This element should be non-zero, if modem
control is required. The CALL element attr is a pointer to
a termio structure, as defined in the termio.h header file.
A NULL value for this pointer element may be passed to the
dial function, but if such a structure is included, the ele-
ments specified in it will be set for the outgoing terminal
line before the connection is established. This is often
important for certain attributes such as parity and baud-
rate.
The CALL element device is used to hold the device name
(cul..) that establishes the connection.
The CALL element dev_len is the length of the device name
that is copied into the array device.
NOTES
Including the <dial.h> header file automatically includes
the <termio.h> header file.
This routine uses <stdio.h>, which increases the size of
programs, even those that don't otherwise use standard I/O,
more than you might expect.
Within dial, an alarm(2) system call is made for 3600
seconds (and caught), for the purpose of ``touching'' the
LCK.. file. This also constitutes the device allocation
semaphore for the terminal device. Otherwise, uucp(1C) may
simply delete the LCK.. entry on its 90-minute clean-up
rounds. This alarm may go off while your program is in a
read(2) or write(2) system call, and cause an error return.
If you expect the program to run for an hour or more, your
program should check error returns from read for
(errno==EINTR), and, possibly, reissue the read.
Dial supports the VADIC 212 autodial modem.
RELATED FILES
/usr/lib/uucp/L-devices
/usr/spool/uucp/LCK..tty-device
DIAGNOSTICS
Upon failure, dial returns a negative value that indicates
the reason for the failure. Mnemonics for the negative
DIAL-2 Printed 5/10/85
DIAL(3C) DOMAIN/IX Reference Manual (SYS5) DIAL(3C)
values listed here are defined in the <dial.h> header file.
INTRPT -1 /* interrupt occurred */
D_HUNG -2 /* dialer hung (no return from write) */
NO_ANS -3 /* no answer within 10 seconds */
ILL_BD -4 /* illegal baud rate */
A_PROB -5 /* acu problem (open() failure) */
L_PROB -6 /* line problem (open() failure) */
NO_Ldv -7 /* can't open LDEVS file */
DV_NT_A -8 /* requested device not available */
DV_NT_K -9 /* requested device not known */
NO_BD_A -10 /* no device available at requested baud */
NO_BD_K -11 /* no device known at requested baud */
RELATED INFORMATION
uucp(1C) alarm(2), read(2), write(2) termio(5)
Printed 5/10/85 DIAL-3