SWI-Prolog Changelog from version 10.1.10 to 10.1.11

[Jul 4 2026]

FIXED: #726 Less confusing message for unbound type in a type_error(Expected,Found) error.
BUILD: Setup library and foreign search paths in the build tree For cross-compilation using the native friend to run the Prolog steps of build, we need to setup library to point at the current (cross) target and foreign to point at the directories holding the foreign modules of the native friend.

[Jul 3 2026]

BUILD: #1503 Simplify the way we setup paths for running in the build directory. The now aproach should notably fix getting paths setup correctly for running the Prolog build steps using a native friend, providing the ability to do cross building where we cannot run the cross-compiled executable and therefore use a native friend to perform these steps.
FIXED: #1093 PL_initialise() no longer mutates the process LC_NUMERIC locale initLocale() used to call setlocale(LC_NUMERIC, "") to bootstrap the default PL_locale from localeconv(). As a side effect it changed the embedder's process-wide decimal separator, breaking atof() and printf("%f") in host code that expects the C locale. Read the environment's numeric conventions via newlocale()/uselocale() (POSIX 2008) instead, with a save/setlocale/restore fallback under L_LOCALE for platforms without them. locale_create/3 uses the same helper.
FIXED: #1386 candidate deep list index preempting deterministic primary For a small static predicate whose primary argument discriminates but whose non-primary compound argument shares a top-level functor across clauses, set_candidate_indexes() emits a list hash index on the compound argument. At call time existing_hash() matched that index (top-level functor bound), the deep drill entered a sub-list whose inner arguments were variables, and the recursion fell back to next_clause_unindexed(), leaving a spurious choice point on the non-matching clause.
FIXED: #1245 wrap_predicate/4 supervisor to carry meta/det qualification prefix. $c_wrap_predicate/5 installed a bare S_CALLWRAPPER supervisor, bypassing the S_MQUAL/S_LMQUAL prefix that chainPredicateSupervisor() normally prepends for meta-predicates. Tracing a meta-predicate such as foldl/4 therefore lost the caller-module context on higher-order arguments, so the wrapped goal looked up my_plus/3 rather than my_plus/3.
FIXED: PL_get_stream() invalid mode detection.

[Jul 2 2026]

FIXED: #1233 PL_get_stream() to verify returned stream has correct (input/output) mode.
FIXED: #1359 nb_setval/2 did not duplicate a plain attvar.

[Jul 1 2026]

DOC: #782 absolute_file_name/3 default behavior when spec resolves to a directory The docs claimed the predicate "only returns non-directories" unless file_type(directory) is given or access is none. Since the default access is none, that "unless" clause covers the default -- but readers naturally miss it. Also, the file_type section stated the opposite of what the code does regarding when file_type(regular) is the default.
DOC: #793 clarify --home and the home Prolog flag Explain what the home directory is used for (boot.prc, library/) and distinguish the two forms of --home: with =DIR sets the home directory (and adds SWI_HOME_DIR to the environment); without argument reports the located home directory. Cross-reference the --home option, the home Prolog flag, and the findhome section from each other. Update both the swipl(1) man page and the user manual.
FIXED: Windows: UNC support for relative file names and shared object loading. When the process working directory is a UNC path (e.g. set via a Windows shortcut's "Start in" field), resolving a relative file name via absolute_file_name/3, access_file/2 and friends failed, and open_shared_object/2, use_foreign_library/1 could not load DLLs identified by a UNC path.
FIXED: #695 number_string/2: correct type error.
FIXED: PL_get_text() with only CVT_STRING to return type_error(string, X)
FIXED: pack installer: consider installed packs when resolving dependencies When installing a pack whose requires only becomes known after download (e.g. installed from a URL), download_plan/3 recursed into pack_resolve/5 with only the just-downloaded plan as Existing, losing the list of locally installed packs. Dependencies already satisfied by an installed pack were then presented as fresh installs and, if the user declined, the whole install failed.

[Jun 30 2026]

FIXED: require_prolog_version/2: Git version comparison.

[Jun 26 2026]

BUILD: detect Intel-Mac Homebrew at /usr/local for dependency paths On Intel Macs, Homebrew installs to /usr/local rather than /opt/homebrew. The auto-detection in Darwin.cmake only checked /opt/homebrew, so Intel Mac users fell through to MACOSX_DEPENDENCIES_FROM=None, leaving LibArchive (and OpenSSL, BDB) unfound by CMake. This caused a broken man/archive file dependency in the Ninja build graph and a ninja failure.

[Jun 27 2026]

ADDED: prolog_edit:locations/2, provide data access to location discovery.
ADDED: help_apropos/4, providing access to the apropos database.

[Jun 25 2026]

FIXED: is_stream/1: crash when querying a standard stream alias whose slot is NULL. In a thread created without PL_THREAD_CUR_STREAMS the protocol slot is never copied, and freeStream() also resets it to NULL when the protocol stream is closed. get_stream_handle() then dereferenced LD->IO.streams[n] without a NULL check. The downstream code already treats NULL as "no such stream", so just guard the SIO_CMAGIC test.

Package clib

[Jun 26 2026]

FIXED: process_create/3: restore signal mask in child before exec SIGPROF is blocked around fork() to keep profiler ticks from interrupting it, but the previous mask was only restored in the parent. The child therefore inherited SIGPROF blocked across execve(), so the new process's ITIMER_PROF profiler ran but no ticks were ever delivered. profile/1 then divided by zero in prolog_profile:show_profile_/1.

Package cpp

[Jul 3 2026]

TEST: Fixed PL_get_stream() calls asking for the wrong in/out stream.

Package http

[Jun 30 2026]

ADDED: library(http/sse): honour http:cors setting in sse_open/0,1 Browser-based EventSource clients on a different origin need an Access-Control-Allow-Origin response header. sse_open/0,1 now calls cors_enable/0 from library(http/http_cors), so the existing http:cors setting controls whether the header is emitted. Non-browser clients and same-origin pages are unaffected (default setting is []).

[Jun 26 2026]

ADDED: library(http/sse): high-level helper for Server-Sent Events sse_open/0,1 emits the response headers and switches the CGI output stream into event_stream transfer mode. sse_send/1,2 writes events given as a dict (with optional event, data, id, retry and comment keys), an atom/string, or a list of events, splitting multi-line data on '\n' into separate "data:" lines. sse_comment/1,2 emits a heartbeat.
FIXED: cgi_stream: stop emitting a second header block when an event_stream handler returns For event_stream responses the headers are sent by cgi_hook(send_header) when the transfer encoding is selected, and each subsequent write is flushed straight through to the client. cgi_close() was still calling the send_header hook again, producing a spurious extra HTTP header block at the end of the body. Skip the call for event_stream; the chunked path is already special-cased.

Package xpce

[Jun 30 2026]

FIXED: terminal: send capital 'O', not digit '0', in DECCKM arrow keys In DEC application cursor mode (DECCKM, \e[?1h), arrow / Home / End should send SS3 sequences \eOA \eOB \eOC \eOD \eOH \eOF, but we sent the digit zero instead of capital O. Vim enables DECCKM via terminfo's smkx, so every arrow press in insert mode bounced vim out of insert mode and ran "0" / "A" as normal-mode commands.
ENHANCED: terminal: DCS swallow, CSI intermediate bytes and OSC 10/11 Vi/vim probes the terminal with sequences our parser did not recognise, which surfaced as ESCP, `ESC\`, `Unknown ANSI CSI: \e[0%andUnknown OSC command: 11` messages, and left vim guessing the colour scheme. Handle them:

[Jun 27 2026]

FIXED: Prevent help_message window from being destroyed.