1 01/24/82  Standard subsystem request:  exec_com, ec
 2 
 3 Syntax:  ec ec_path {ec_args}
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 5 
 6 Syntax as an active request:  [ec ec_path {ec_args}]
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 8 
 9 Function:  executes a program written in the exec_com language which is
10 used to pass request lines to the subsystem and to pass input lines to
11 requests which read input.  As an active request, the exec_com program
12 specifies a return value of the exec_com request by use of the &return
13 statement.
14 
15 
16 Arguments:
17 ec_paths
18    is the pathname of an exec_com program.  The suffix, which is
19    normally the name of the subsystem, is assumed if not specified.
20 ec_args
21    are optional arguments to the exec_com program and are substituted
22    for parameter references in the program such as &1.
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24 
25 Notes:
26 Subsystems may define a search list to be used to find the exec_com
27 program.  If this is the case, the search list is used if ec_path does
28 not contain a "<" or ">" character; if the ec_path does contain either
29 a "<" or ">", it is assumed to be a relative pathname.
30 
31 For a description of the exec_com language (both version 1 and
32 version 2), type:
33    .. help v1ec v2ec
34 
35 When evaluating a subsystem exec_com program, subsystem active
36 requests are used rather than Multics active functions when evaluating
37 the &[...] construct and the active string in an &if statement.  The
38 subsystem's execute active request may be used to evaluate Multics
39 active strings within the exec_com.
40 
41 
42 Limitation:
43 In the present implementation, any errors detected during execution of
44 an exec_com within a subsystem will abort the request line in which the
45 exec_com request was invoked.