9.2 Guide to Porting Code from Release 3

Release 4 does not provide a mode in which it is 100% compatible with earlier releases. However, this section provides guidelines for migrating Prolog code from release 3 to release 4.

  1. First of all, make sure that your code runs in ISO execution mode. In release 3, the command line option --iso can be used.
  2. A number of built-in predicates have been dropped. They are listed in the table below, along with their approximate substitutes. Refer to the documentation for each case.

    Dropped built-in Replaced by


    get0/[1,2], get/[1,2] get_code/[1,2], get_byte/[1,2]


    ttyget0/1, ttyget/1 get_code/2, get_byte/2


    put/[1,2], tab/[1,2] put_code/[1,2], put_byte/[1,2]


    ttyput/1, ttytab/1 put_code/2, put_byte/2


    skip/[1,2] skip_code/[1,2], skip_byte/[1,2]


    ttyskip/1 skip_code/2, skip_byte/2


    ttynl/0 nl/1


    ttyflush/0 flush_output/1


    fileerrors/0, nofileerrors/0 set_prolog_flag/2


    'C'/3 unification


    call_residue/2 call_residue_vars/2


    undo/1 prolog:undo/1


    help/0 the message system


    version/0 the message system


    version/1 the message system


    fcompile/1 save_files/2


    load/1 load_files/2


    load_foreign_files/2 splfr + load_foreign_resource/1


    require/1 use_module/2


    is_mutable/1 mutable/1


    module/1 set_module/1
  3. The hook predicates user:term_expansion/[2,4] and user:term_expansion/3 are now called user:term_expansion/6 and Module:term_expansion/5 and have a modified API; see Term and Goal Expansion.
  4. The set of library modules has been enriched by incorporating a subset of the Quintus Prolog library modules that we have deemed useful.

    The following library modules are not included in SICStus 4: clpb, flinkage, spaceout. library(objects) has been replaced by its Quintus counterpart, with a completely different API.

    The following table lists the affected SICStus 3 library modules.

    Affected module Closest equivalent Comment


    arrays arrays3 a


    assoc assoc3 b


    charsio codesio c


    clpfd clpfd d


    lists lists3 e


    queues queues3 f


    random random3 g


    sockets sockets d


    system system3 h

    Comments to the table:

    1. library(arrays3) is a code migration library module; the long-term solution is to use library(logarrs) instead.
    2. library(assoc3) is a code migration library module; the long-term solution is to use library(avl) instead.
    3. The syllable `chars' has been changed to `codes' throughout.
    4. Several API changes; see the documentation.
    5. library(lists3) is a code migration library module; the long-term solution is to use library(lists) instead.
    6. library(queues3) is a code migration library module; the long-term solution is to use library(queues) instead.
    7. library(random3) is a code migration library module; the long-term solution is to use library(random) instead.
    8. library(system3) is a code migration library module; the long-term solution is to use library(system), library(file_systems) and library(process) instead.

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