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. Extended runtime systems do provide 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.