NAME

dial − establish an out-going terminal line connection

SYNOPSIS

#include <dial.h>

int dial (call)
CALL ∗call;

void undial (fd)
int fd;

DESCRIPTION

Dial returns a file-descriptor for a terminal line open for read/write.  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 has been set during the allocation of the terminal device. 

The CALL typedef in the <dial.h> header file is:

typedef struct {

struct termio∗attr;/∗ pointer to termio attribute struct ∗/
intbaud;/∗ transmission data rate ∗/
intspeed;/∗ 212A modem: low=300, high=1200 ∗/
char∗line;/∗ device name for out-going line ∗/
char∗telno;/∗ pointer to tel-no digits string ∗/
intmodem;/∗ specify modem control for direct lines ∗/

} CALL;

The CALL element speed is intended only for use with an outgoing dialed call, in which case its value should be either 300 or 1200 to identify the 113A modem, or the high or low speed setting on the 212A modem.  The CALL element baud is for the desired transmission baud rate.  For example, one might set baud to 110 and speed to 300 (or 1200). 

If the desired terminal line is a direct line, a string pointer to its device-name should be placed 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 the baud element need not be specified as it will be determined from the L-devices file. 

The telno element is for a pointer to a character string representing the telephone number to be dialed.  The termination symbol will be supplied by the dial function, and should not be included in the telno string passed to dial in the CALL structure. 

The CALL element modem is used 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 elements 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. 

FILES

/usr/lib/uucp/L-devices
/usr/spool/uucp/LCK..tty-device

SEE ALSO

uucp(1C), alarm(2), read(2), write(2), termio(7)

DIAGNOSTICS

On failure, a negative value indicating the reason for the failure will be returned.  Mnemonics for these negative indices as 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 ∗/

WARNINGS

Including the <dial.h> header file automatically includes the <termio.h> header file. 

The above routine uses <stdio.h>, which causes it to increase the size of programs, not otherwise using standard I/O, more than might be expected. 

BUGS

An alarm(2) system call for 3600 seconds is made (and caught) within the dial module for the purpose of “touching” the LCK.. file and 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.  The alarm may go off while the user program is in a read(2) or write(2) system call, causing an apparent error return. If the user program expects to be around for an hour or more, error returns from reads should be checked for (errno==EINTR), and the read possibly reissued. 

Version 2.5  —  April 22, 1987