When users log on, they can specify MAIL, NOTICES, or both, but they do not issue the LISTBC command. Therefore, when LISTBC invokes the initialization exit, there is no command buffer. Figure 1 shows the key, length, and data values for the command buffer (parameter entry 1) when the LISTBC initialization exit receives control during logon processing. The key of X'00' indicates that no data is passed in the parameter entry.

Figure 1. Command buffer parameter entry when LISTBC initialization exit gets control during logon

Figure 2 shows the exit-dependent data that the LISTBC initialization exit receives when it gets control during logon processing. The exit-dependent data begins at offset +36 (decimal) in the parameter list. Each parameter entry is described following the figure.

Figure 2. Exit-Dependent data for the LISTBC initialization exit during logon processing

Control Block (Parameter Entry 10)

This parameter entry contains the address of the copy of the SEND PARMLIB control block. For a description of the control block, see Table 1.

Flags (Parameter Entry 11)

When users log on to TSO/E, they can specify MAIL or NOMAIL and NOTICES or NONOTICES. This parameter entry contains LISTBC indicator flags. The flags indicate whether the user specified MAIL/NOMAIL and NOTICES/NONOTICES.

Although there is no command buffer you can use to modify processing, you can change the indicator flag bits to control and customize processing. For example, you can use the bits to ensure that users receive mail and notices when they log on. Table 1 shows the format of the LISTBC indicator flags, which consist of 32 bits.

Table 1. Format of the LISTBC indicator fags

Bit	Description
1	Indicates whether the user specified MAIL or NOMAIL. 0 - the user specified NOMAIL 1 - the user specified MAIL
2	Indicates whether the user specified NOTICES or NONOTICES. 0 - the user specified NONOTICES 1 - the user specified NOTICES
3-32	Reserved