6.7.1 Runtime Systems

Stand-alone applications containing debugged Prolog code and destined for end-users are typically packaged as runtime systems. No SICStus license is needed by a runtime system. A runtime system has the following limitations:

• No top-level. The executable will restore a saved-state and/or load code, and call user:runtime_entry(start). Alternatively, you may supply a main program and explicitly initialize the Prolog engine with SP_initialize(). break/0 and require/1 are unavailable.
• No debugger. debugging, debug and debugger_print_options have no effect. Predicates annotated as [development] in the reference pages are unavailable.
• Except in extended runtime systems: no compiler; compiling is replaced by consulting.

  While consulting without the compiler, if clauses for an existing, compiled, multifile predicate are encountered, the existing clauses remain untouched, the multifile clauses being consulted are simply skipped with a permission error, and the consult continues.

  The extended runtime system provides the compiler.

• The Prolog flags discontiguous_warnings and single_var_warnings have no effect.
• The redefine_warnings Prolog flag is off by default, suppressing queries and warnings about name clashes and redefinitions.
• The informational Prolog flag is off by default, suppressing informational messages.
• No profiler or coverage analysis. The predicates profile_reset/0, profile_data/1, print_profile/[0,1] coverage_data/1, and print_coverage/[0,1] are unavailable. The Prolog flag profiling is unavailable.
• No signal handling except as installed by SP_signal().

It is possible to tell a runtime system to start a development system instead, for debugging purposes. See Debugging Runtime Systems for details.