# I have a nice and complicated crash **URL:** \ **Category:** Help!\ **Created:** [October 17, 2025, 7:58am UTC](https://swi-prolog.discourse.group/t/i-have-a-nice-and-complicated-crash/9350 "2025-10-17T07:58:27Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Frank\_Schwidom](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/frank_schwidom/32/7662_2.png) [@Frank\_Schwidom](https://swi-prolog.discourse.group/u/Frank_Schwidom)\ **Post date:** [October 17, 2025, 7:58am UTC](https://swi-prolog.discourse.group/t/i-have-a-nice-and-complicated-crash/9350/1 "2025-10-17T07:58:27Z")
I’m using: SWI-Prolog version threaded, 64 bits, version 9.3.20-DIRTY I put the following code in the console and first an errormessage comes up which is expected but then I use the cursor up to regain the same input again and press enter (using the cursor makes the difference). (ins)$ swipl Welcome to SWI-Prolog (threaded, 64 bits, version 9.3.20-DIRTY) SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software. Please run ?- license. for legal details. For online help and background, visit [https://www.swi-prolog.org](https://www.swi-prolog.org) For built-in help, use ?- help(Topic). or ?- apropos(Word). ```prolog (ins)?- TERM = forall( ( current_input(_4504),repeat,read_string(_4504,' \n','',_11990,_11992),meta( _OX)),(writeln(_3548),_3554\== -1)), TERM. ERROR: Unknown procedure: meta/1 ERROR: In: ERROR: [15] meta(_14818) ERROR: [14] ''(user:(...,...)) ERROR: [13] forall(user:(...,...),user:(...,...)) at /usr/local/lib/swipl/boot/apply.pl:52 ERROR: [12] ''(user:user: ...) ERROR: [11] toplevel_call(user:user: ...) at /usr/local/lib/swipl/boot/toplevel.pl:1319 Exception: (15) meta(_1924) ? abort % Execution Aborted (ins)?- ``` So far so good, now the cursor thingy (cursor up, enter): ```prolog (ins)?- TERM = forall( ( current_input(_4504),repeat,read_string(_4504,' \n','',_11990,_11992),meta( _OX)),(writeln(_3548),_3554\== -1)), TERM. (ins)|: ``` Unexpectedly the code compiles and I come into an input request. When I now input “abc def” and press enter I get the crash: ```prolog (ins)|: abc def ERROR: Unknown procedure: meta/1 ERROR: In: ERROR: [15] meta(_2902) ERROR: [14] ''(user:(...,...)) ERROR: [13] forall(user:(...,...),user:(...,...)) at /usr/local/lib/swipl/boot/apply.pl:52 ERROR: [12] ''(user:user: ...) ERROR: [11] toplevel_call(user:user: ...) at /usr/local/lib/swipl/boot/toplevel.pl:1319 Exception: (15) meta(_1242) ? depth ERROR: Received fatal signal 11 (segv) Time: Fri Oct 17 09:57:12 2025 Inferences: 536425 Thread: 1 (main) C-stack trace labeled "crash": [0] save_backtrace() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/os/pl-cstack.c:337 [0x7fde52944a9e] [1] sigCrashHandler() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/os/pl-cstack.c:937 [0x7fde52944b69] [2] __restore_rt() at sigaction.c:? [0x7fde5266ede0] [3] wsizeofInd() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/pl-data.h:310 [0x7fde5290b0dc] [4] firstClause___LD() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/pl-index.c:783 [0x7fde5290bb58] [5] PL_next_solution___LD() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/pl-vmi.c:3429 [0x7fde52839245] [6] PL_call_predicate() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/pl-fli.c:4534 [0x7fde5291674f] [7] setPrintOptions() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/pl-trace.c:641 [0x7fde528ae2c6] [8] traceAction() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/pl-trace.c:750 [0x7fde528b1ddc] [9] PL_next_solution___LD() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/pl-vmi.c:5118 [0x7fde52836b3d] [10] query_loop() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/pl-pro.c:179 [0x7fde5288ec91] [11] prologToplevel() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/pl-pro.c:655 [0x7fde5288f73d] [12] PL_toplevel() at /home/ox_external_source/sources_external/swi-prolog-github/swipl-devel/src/pl-fli.c:4999 [0x7fde5291788e] [13] swipl(+0x10b5) [0x556e9c4a60b5] [14] __libc_start_main() at ./csu/../csu/libc-start.c:308 [0x7fde52659d7a] [15] swipl(+0x10fa) [0x556e9c4a60fa] PROLOG STACK (without arguments): [17] system:$set_debugger_write_options/1 [16] system:$c_call_prolog/0 [PC=0 in top query clause] [15] meta/1 [14] system:/1 [PC=19 in clause -1] [13] $apply:forall/2 [PC=6 in clause 1] [12] system:/1 [PC=6 in clause -1] [11] $toplevel:toplevel_call/1 [PC=3 in clause 1] [10] $toplevel:stop_backtrace/2 [PC=4 in clause 1] [9] $tabling:$wfs_call/2 [PC=17 in clause 1] [7] $toplevel:$execute_goal2/3 [PC=31 in clause 1] PROLOG STACK (with arguments; may crash if data is corrupted): [17] Speicherzugriffsfehler ``` ---
**Author:** ![Frank\_Schwidom](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/frank_schwidom/32/7662_2.png) [@Frank\_Schwidom](https://swi-prolog.discourse.group/u/Frank_Schwidom)\ **Post date:** [October 17, 2025, 8:04am UTC](https://swi-prolog.discourse.group/t/i-have-a-nice-and-complicated-crash/9350/2 "2025-10-17T08:04:43Z")
Just in case it is not reproducible: This all happens on an ordinary lxterminal 0.4.0 and prolog configured to use readline (vi bindings). But I guess this is a caching thing. ---
**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\ **Post date:** [October 17, 2025, 10:01am UTC](https://swi-prolog.discourse.group/t/i-have-a-nice-and-complicated-crash/9350/3 "2025-10-17T10:01:13Z")
Thanks for reporting. Looks like some memory management issue. But, we are at 9.3.32 and the GNU readline package for SWI-Prolog is discontinued. Works fine in 9.3.32 under AddressSanitizer. P.s. That said, 9.3.32 has a serious memory management issue in the `swipl-win` console. Fixe in the git version. ---
**Author:** ![Frank\_Schwidom](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/frank_schwidom/32/7662_2.png) [@Frank\_Schwidom](https://swi-prolog.discourse.group/u/Frank_Schwidom)\ **Post date:** [October 17, 2025, 10:32am UTC](https://swi-prolog.discourse.group/t/i-have-a-nice-and-complicated-crash/9350/4 "2025-10-17T10:32:40Z")
> [@jan](#): > > GNU readline package for [SWI-Prolog](https://www.swi-prolog.org/pldoc/doc_for?object=manual) is discontinued Sad. I hope I get rlwrap wrapped around swi prolog. ---
**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\ **Post date:** [October 17, 2025, 11:10am UTC](https://swi-prolog.discourse.group/t/i-have-a-nice-and-complicated-crash/9350/5 "2025-10-17T11:10:22Z")
> [@Frank\_Schwidom](#): > > Sad. I hope I get rlwrap wrapped around swi prolog. If you want `vi`, ``` ?- el_bind(user_input, ['-v']). ``` To use that everywhere and always, add this to your `init.pl`: ```prolog :- multifile editline:el_setup/1. editline:el_setup(Stream) :- el_bind(Stream, ['-v']). ``` Or, add this to `~/.editrc` (or simply `bind -v` to address all programs using editline). ``` swipl:bind -v ``` `rlwrap` works to some extend. I use it with other Prolog systems that have no built-in commandline editing. This notably lacks Prolog specific completion though.