dial(3C)dial(3C)NAMEdial(), undial() - establish an outgoing terminal line connection
The function returns a file descriptor for a terminal line open for
read/write. The argument to is a structure (defined in the header
When finished with the terminal line, the calling program must invoke
to release the semaphore that has been set during the allocation of the
The definition of in the header file is:
elements are as follows:
speed 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. Note that the 113A modem
or the low-speed setting of the 212A modem transmits
at any rate between 0 and 300 bits per second. How‐
ever, the high-speed setting of the 212A modem trans‐
mits and receives at 1200 bits per second only.
baud Desired transmission baud rate. For example, one
might set baud to 110 and speed to 300 (or 1200).
However, if speed is set to 1200, baud must be set to
line 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 structure. Legal values for
such terminal device names are kept in the file. In
this case, the value of the baud element need not be
specified as it will be determined from the file.
telno A pointer to a character string representing the tele‐
phone number to be dialed. Such numbers can consist
only of symbols described below. The termination sym‐
bol is supplied by the function, and should not be
included in the telno string passed to in the struc‐
4-second delay for second dial tone
End of number
Wait for secondary dial tone
Flash off-hook for 1 second
modem Specifies modem control for direct lines. Set to non-
zero if modem control is required.
attr Pointer to a structure, as defined in the header file.
A NULL value for this pointer element can be passed to
the function, but if such a structure is included, the
elements specified in it are set for the outgoing ter‐
minal line before the connection is established. This
is often important for certain attributes such as par‐
ity and baud rate.
device Holds the device name that establishes the connection.
dev_len Length of the device name that is copied into the
On failure, a negative value indicating the reason for the failure is
returned. Mnemonics for these negative indices as listed here are
defined in the header file.
Including the header file automatically includes the header file.
The above routine uses which causes unexpected increases in the size of
programs that otherwise do not use standard I/O.
The function will modify the values of some of the fields of the struc‐
ture so if is reinvoked, it will reinitialize the values of the struc‐
FILESSEE ALSOuucp(1), alarm(2), read(2), write(2), thread_safety(5), termio(7).
UUCP tutorial in