Miscellaneous

• The new built-ins read_line/[1,2] read one line of input into a list of character codes.
• The new built-in stream_position_data/3 accesses the fields of a stream position term.
• The new built-in goal_source_info/3 decomposes annotated goals into a goal proper and a source position. Mostly used in displaying error messages.
• The built-in undo/1, which posts a goal for execution on backtracking, has been revived.
• absolute_file_name/3 is a new variant of absolute_file_name/2 taking a number of options to give full control over the conversion from relative to absolute filename.
• read_term/[2,3] takes a new option which controls whether the layout-text-item which follows the terminating . should be consumed.
• A resource error exception is raised when there is insufficient memory to continue execution. In previous versions, this condition caused SICStus Prolog to abort the computation and to reinitialize itself.
• trimcore/0 trims the Prolog stacks.
• Debugger changes:
  • Breakpoint conditions now can contain the usual Prolog connectives ,, ;, ->, and \+.
  • A breakpoint for which the test conditions evaluated successfully is always applied, even if the action conditions fail.
  • A hook, user:breakpoint_expansion/2, has been added for user defined breakpoint conditions.
  • Advice-points are now allowed to set all three action variables (mode, show, command).
• library(bdb) provides a way to flush all modified records to disk after each operation.
• library(charsio) provides the new predicates read_term_from_chars/3 and write_term_to_chars/[3,4].
• library(system) provides the new predicates now/1 and datime/2.
• library(clpq,clpr) provides the new predicate projecting_assert/1.
• SP_set_read_hook() is now obsolescent. See Hooks.
• SP_event() can now be called from arbitrary OS threads. See Calling Prolog Asynchronously.
• splfr generates a header file from the foreign/[2,3] declarations. This file should be included in the corresponding C file to protect against incorrect foreign declarations and also to ensure compatibility with various compile time settings used by splfr.

  The name of the file can be specified with --header=NAME. To produce the file and nothing more, you can use the new --nocompile flag as in

            splfr --header=foo.h --nocompile foo.pl
            

  This is especially useful when foo.h is a Makefile prerequisite.

• splfr and spld now use descriptive names for generated files, especially when the flag --keep is specified.
• On Windows, it is now possible to link an application with a static version of the SICStus run-time. It is also possible to link with static versions of foreign resources.
• A statically linked SICStus run-time can load foreign resources dynamically.
• spld --moveable now produces an executable which can be moved, together with its directory tree (see Runtime Systems on Target Machines) on Solaris and Linux (it always worked on Windows).
• New spld options,

  --lang

  Selects the Prolog dialect used for run-time systems created with --main=load and --main=restore.
  

  --memhook

  Selects memory allocation method (SP_set_memalloc_hooks).

  You can use spld --help to get details on these and other options.
• The development system (sicstus and, on Windows, spwin) now take option --iso and --sicstus to start up in ISO Prolog mode and SICStus Prolog mode respectively.
• New C preprocessor macros with version info are now defined when including <sicstus/sicstus.h>. For SICStus 3.9.1, they are defined as:

            #define SICSTUS_MAJOR_VERSION 3
            #define SICSTUS_MINOR_VERSION 9
            #define SICSTUS_REVISION_VERSION 1
            #define SICSTUS_BETA_VERSION 0
            
            /* Two digit position for MAJOR, MINOR and REVISION */
            #define SICSTUS_VERSION 30901
            

• New C API function SP_read_from_string takes a string representation of a Prolog term and a table of variable values and creates a Prolog term. By reading a goal from a string and passing the resulting term to call/1, this also gives a very simple way to call arbitrary goals from C. See Mixing C and Prolog.
• New C API function SP_define_c_predicate makes it possible to dynamically define a Prolog predicate that calls a C function. See Mixing C and Prolog.
• New C API functions SP_mutex_lock, SP_mutex_unlock, C type SP_mutex and static initializer SP_MUTEX_INITIALIZER. These provide a platform independant (recursive) mutual exclusion lock. These are mainly useful when more than one SICStus run-time is used (in different threads) in the same process. See Operating System Services.
• The environment variables SP_APP_DIR and SP_RT_DIR are set (by SP_initialize) to the folder containing the executable and the folder containing the SICStus run-time, respectively. This provides a location independent way to locate files (such as saved states) that are located together with the application. Also available as the file search aliases application and runtime. See Input Output.
• On Win32, the C signal SIGBREAK will cause halt/0 to be called in a development system. This will ensure that halt/0 is called in sicstus.exe when the console window is closed or when the user logs off. The windowed version of SICStus (spwin.exe) also sends itself a SIGBREAK when the GUI window is closed, causing halt/0 to be called.