dial(3C)            (C Programming Language Utilities)             dial(3C)


   NAME
         dial - establish an outgoing terminal line connection

   SYNOPSIS
         #include <dial.h>

         int dial(CALL call);

         void undial(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 definition of CALL in the dial.h header file is:

         typedef struct {
              struct termio *attr;   /* ptr to termio attribute struct */
              int     baud;  /* unused */
              int     speed; /* 212A modem: low=300, high=1200 */
              char    *line; /* device name for out-going line */
              char    *telno;        /* pointer to tel-no/system name string */
              int     modem; /* unused */
              char    *device;       /* unused */
              int     devlen;       /* unused */
         } 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. 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 is
         for the 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 high (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 Devices file.  In this case, the value of the baud element should
         be set to -1.  This value will cause dial to determine the correct
         value from the Devices file.




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   dial(3C)            (C Programming Language Utilities)             dial(3C)


         The telno element is for a pointer to a character string representing
         the telephone number to be dialed.  Such numbers may consist only of
         these characters:
           0-9  dial 0-9
           *    dial *
           #    dial #
           =    wait for secondary dial tone
           -    delay for approximately 4 seconds

         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 setting is
         often important for certain attributes such as parity and baud-rate.

         The CALL elements device and devlen are no longer used.  They are
         retained in the CALL structure for compatibility reasons.

   FILES
         /etc/uucp/Devices
         /etc/uucp/Systems
         /var/spool/uucp/LCK..tty-device

   SEE ALSO
         alarm(2), read(2), write(2).
         termio(7) in the System Administrator's Reference Manual.
         uucp(1C) in the User's Reference Manual.

   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 */
              DHUNG  -2     /* dialer hung (no return from write) */
              NOANS  -3     /* no answer within 10 seconds */
              ILLBD  -4     /* illegal baud-rate */
              APROB  -5     /* acu problem (open() failure) */
              LPROB  -6     /* line problem (open() failure) */
              NOLdv  -7     /* can't open Devices file */
              DVNTA -8     /* requested device not available */
              DVNTK -9     /* requested device not known */
              NOBDA -10    /* no device available at requested baud */
              NOBDK -11    /* no device known at requested baud */
              DVNTE -12    /* requested speed does not match */
              BADSYS -13    /* system not in Systems file*/





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   dial(3C)            (C Programming Language Utilities)             dial(3C)


   NOTES
         Including the dial.h header file automatically includes the termio.h
         header file.
         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.









































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