1 07/06/87  exec_com, ec
 2 
 3 Syntax:  ec ec_path {ec_args}
 4 
 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_path
18    is the pathname of an exec_com program.  The lsec suffix is assumed
19    if not specified.  If only an entryname is given, ssu_ looks for the
20    exec_com in the directories given in the exec_com search list.
21 ec_args
22    are optional arguments to the exec_com program and are substituted
23    for parameter references in the program such as &1.
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25 
26 Notes:
27 Subsystems may define a search list to be used to find the exec_com
28 program.  If this is the case, the search list is used if ec_path does
29 not contain a "<" or ">" character; if the ec_path does contain either
30 a "<" or ">", it is assumed to be a relative pathname.
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32 
33 When evaluating a subsystem exec_com program, subsystem active
34 requests are used rather than Multics active functions when evaluating
35 the &[...] construct and the active string in an &if statement.  The
36 subsystem's execute active request may be used to evaluate Multics
37 active strings within the exec_com.
38 
39 
40 Limitation;
41 In the present implementation, any errors detected during execution of
42 an exec_com within a subsystem will abort the request line in which the
43 exec_com request was invoked.