1/*  Part of SWI-Prolog
    2
    3    WWW:           http://www.swi-prolog.org
    4    Copyright (c)  2020, SWI-Prolog Solutions b.v.
    5    All rights reserved.
    6
    7    Redistribution and use in source and binary forms, with or without
    8    modification, are permitted provided that the following conditions
    9    are met:
   10
   11    1. Redistributions of source code must retain the above copyright
   12       notice, this list of conditions and the following disclaimer.
   13
   14    2. Redistributions in binary form must reproduce the above copyright
   15       notice, this list of conditions and the following disclaimer in
   16       the documentation and/or other materials provided with the
   17       distribution.
   18
   19    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   20    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   21    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   22    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   23    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   24    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   25    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   26    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   27    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   29    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   30    POSSIBILITY OF SUCH DAMAGE.
   31*/
   32
   33:- module(sicstus4_system,
   34	  [ environ/2,			% ?Name, ?Value
   35	    environ/3			% ?Name, ?Value, +Source
   36	  ]).   37:- reexport('../sicstus/system',
   38	    [ now/1,
   39	      datime/1,
   40	      datime/2,
   41	      sleep/1
   42	    ]).   43
   44:- multifile sicstus4:rename_module/2.   45
   46sicstus4:rename_module(system, sicstus4_system).

 environ(?Name, ?Value) is nondet

 environ(?Name, ?Value, +Source) is nondet

True if Value is an atom associated with the environment variable or system property Name.

Source may be properties (to get only system properties), environment (to get only environment variables), or merged (the default, to get both, with system properties taking precedence over environment variables of the same name).

Compatibility

- SICStus 4

To be done

- Mode -Name is not supported.

Because SWI-Prolog doesn't have an obvious equivalent to
SICStus system properties, these predicates currently
behave as if no system properties are defined,
i. e. only environment variables are returned.

   73environ(_Name, _Value, properties) :- fail.
   74environ(Name, Value, environment) :- getenv(Name, Value).
   75environ(Name, Value, mixed) :-
   76	(   environ(Name, Value, properties)
   77	->  true
   78	;   environ(Name, Value, environment)
   79	).
   80environ(Name, Value) :- environ(Name, Value, mixed)