1 10/17/84  signal
 2 
 3 Syntax as a command:  signal CONDITION_NAME {-control_args}
 4 
 5 
 6 Function:  signals Multics conditions, allowing you to specify some
 7 information to be associated with the condition.  The result of a
 8 condition signal depends on your program or the system program handling
 9 the condition signal.
10 
11 
12 Arguments:
13 CONDITION_NAME
14    is the name of the condition to signal.  It can't contain embedded
15    white space because condition names are only significant to the
16    first space character.  It can't be longer than 256 characters.
17 
18 
19 Control arguments:
20 -cant_restart
21    sets the cant_restart flag for this signal.  The default handler
22    establishes a new listener level after printing a message and
23    refuses to accept the start command.  (See "Notes.")
24 -code ET_CODE_NAME
25    associates the error table code name ET_CODE_NAME with this signal.
26    It must be a virtual pointer to an error table acceptabe to cv_ptr_.
27    If you omit the segment name portion of the virtual pointer,
28    error_table_ is assumed.  The text message defined for this error
29    table code is printed if an error message is printed; thus an
30    ET_CODE_NAME of noentry is interpreted as error_table$noentry, not
31    as a pointer to noentry|0.
32 
33 
34 -default_restart
35    sets the default_restart flag for this signal.  The default handler
36    prints a message and restarts execution.
37 -info_string INFO_MESSAGE
38    associates the string INFO_MESSAGE with this signal.  If an error
39    message is printed, this string is also printed.  Enclose it in
40    quotes if it contains white space or special characters.  The string
41    can't be longer than 256 characters.
42 
43 
44 -quiet_restart
45    sets the quiet_restart flag for this signal.  The default handler
46    restarts execution without printing a message.
47 -support_signal
48    sets the support_signal flag for this signal.  This indicates that
49    the error is being signaled on behalf of another procedure and
50    should only be used when your handler is present on the stack that
51    expects it.
52 
53 
54 Notes:  The descriptions that follow assume that the signal is handled
55 by the default unclaimed signal handler (default_error_handler_$wall).
56 Any messages described are sent over the error_output switch.
57 
58 Don't use this command with any of the system conditions defined in the
59 Programmer's Reference Manual or with PL/I language conditions because
60 they require other associated information that you can't specify with
61 signal and unpredictable results may occur.
62 
63 You can use the on command to handle signals produced with this
64 command.
65 
66 
67 The default handler deals with all condition signals that are otherwise
68 unhandled by your programs or system programs on the stack.  If you
69 select none of -cant_restart, -default_restart, or -quiet_restart, the
70 default handler prints the error message described below, and
71 establishes a new listener level.  If you type "start" at this point,
72 execution continues.  If the command is executed in an exec_com and you
73 type start, execution continues with the next command in the exec_com.
74 
75 The default message printed for a condition signaled is of the form
76    Error: CONDITION_NAME condition by signal$signal|octalnumber
77    ERROR_TABLE_MESSAGE
78    INFO_STRING_MESSAGE
79 
80 If you give no -info_string, the INFO_STRING_MESSAGE line is omitted.
81 If you don't chose -code, the ERROR_TABLE_MESSAGE line is omitted.