libpcre3, which is used by SIMH, has been removed from Ubuntu Trixie. Compiling with libpcre2 works but simh does not run.

[mkatzpdp]

libpcre3, which is used by SIMH, has been removed from Ubuntu Trixie for security reasons.

Substituting libpcre2 (A newer version) will compile but simh hangs on run.

This has been verified on Raspberry Pi trixie and WSL Ubuntu.

Either remove the dependencies on libpcre3 or modify the code to use libpcre2.

[markpizz]

I can't say with authority about the build success of open-simh/simh, I know that open-simh/simh has migrated to use the libpcre2 APIs. Meanwhile when I looked at this a few years back, libpcre3 included the libpcre2 library, so the functionality is there already.

[mkatzpdp]

Both myself and one other user have verified this issue. Building with libpcre2 cause simh to hang on the go command

It hangs on the go command in the following pdp8.ini file:

:starter
SET ON
ON OPENERR
ON OPENERR GOTO telerr
at ttix 2222;notelnet
set ttox0 8b
echo Starting socat...
#! sleep 1
! socat PTY,echo=0,link=ttyPDP TCP:localhost:2222 &
echo Waiting for socat...
! sleep 1
echo Starting SerialDisk server...
! xterm -e "bash -c "../server/os8disk -1 ../disks/diagpack2_new2.rk05; exec bash"" &
! sleep 1
echo Booting...
l ../bootloader/bootloader.bin
go
:byebye
detach ttix
quit
:telerr
echo TTIX has not released port. Retrying now...
! sleep 2
goto starter

[markpizz]

When I build the pdp8 simulator from the last commit in the open-simh/simh master branch on the latest Ubuntu (26.04), I see this output:
mark@Ubuntu-26.04:$../open-simh$ make pdp8
lib paths are: /usr/lib/wsl/lib/ /usr/lib/x86_64-linux-gnu/ /usr/lib/x86_64-linux-gnu/libfakeroot/ /lib/ /usr/lib/
include paths are: /usr/lib/gcc/x86_64-linux-gnu/15/include /usr/local/include /usr/include/x86_64-linux-gnu /usr/include
using libm: /usr/lib/x86_64-linux-gnu/libm.so
using librt: /usr/lib/x86_64-linux-gnu/librt.a
using libpthread: /usr/lib/x86_64-linux-gnu/libpthread.a /usr/include/pthread.h
using libpcre2-8: /usr/lib/x86_64-linux-gnu/libpcre2-8.so /usr/include/pcre2.h
using semaphore: /usr/include/semaphore.h
using libdl: /usr/lib/x86_64-linux-gnu/libdl.a /usr/include/dlfcn.h
using libedit: /usr/include/editline/readline.h
using libpng: /usr/lib/x86_64-linux-gnu/libpng.so /usr/include/png.h
using zlib: /usr/lib/x86_64-linux-gnu/libz.so /usr/include/zlib.h
using mman: /usr/include/x86_64-linux-gnu/sys/mman.h
using libSDL2: /usr/include/SDL2/SDL.h
*** No SDL ttf support available. BESM-6 video panel disabled.
***
*** Info *** Install the development components of libSDL2-ttf
*** Info *** packaged for your Linux operating system distribution:
*** Info *** $ sudo apt-get install libsdl2-ttf-dev
***
*** pdp8 Simulator being built with:
*** - compiler optimizations and no debugging support. GCC Version: 15.2.0.
*** - video capabilities provided by libSDL2 (Simple Directmedia Layer).
*** - Per simulator tests will be run.
***
*** git commit id is a1f57fa.
*** git commit time is 2026-07-03T13:48:11+0200.
***
gcc -std=gnu99 -U__STRICT_ANSI__ -O2 -DNDEBUG=1 -finline-functions -fgcse-after-reload -fpredictive-commoning -fipa-cp-clone -fno-unsafe-loop-optimizations -fno-strict-overflow -DSIM_GIT_COMMIT_ID=a1f57fa3738ed31148d31126ba1a7278ff845c6d -DSIM_GIT_COMMIT_TIME=2026-07-03T13:48:11+0200 -DSIM_COMPILER="GCC Version: 15.2.0" -DSIM_BUILD_TOOL=simh-makefile -I . -Werror -D_GNU_SOURCE -DHAVE_PCRE2_H -DHAVE_SEMAPHORE -DHAVE_SYS_IOCTL -DHAVE_LINUX_CDROM -DSIM_HAVE_DLOPEN=so -DHAVE_EDITLINE -DHAVE_UTIME -DHAVE_LIBPNG -DHAVE_ZLIB -DHAVE_GLOB -DHAVE_SHM_OPEN ./PDP8/pdp8_cpu.c ./PDP8/pdp8_clk.c ./PDP8/pdp8_df.c ./PDP8/pdp8_dt.c ./PDP8/pdp8_lp.c ./PDP8/pdp8_mt.c ./PDP8/pdp8_pt.c ./PDP8/pdp8_rf.c ./PDP8/pdp8_rk.c ./PDP8/pdp8_rx.c ./PDP8/pdp8_sys.c ./PDP8/pdp8_tt.c ./PDP8/pdp8_ttx.c ./PDP8/pdp8_rl.c ./PDP8/pdp8_tsc.c ./PDP8/pdp8_td.c ./PDP8/pdp8_ct.c ./PDP8/pdp8_fpp.c ./PDP8/pdp8_dpy.c ./display/display.c ./display/sim_ws.c ./scp.c ./sim_console.c ./sim_fio.c ./sim_timer.c ./sim_sock.c ./sim_tmxr.c ./sim_ether.c ./sim_tape.c ./sim_disk.c ./sim_serial.c ./sim_video.c ./sim_imd.c ./sim_card.c -I ./PDP8 -DUSE_DISPLAY -DHAVE_LIBSDL -DUSE_SIM_VIDEO sdl2-config --cflags sdl2-config --libs -o BIN/pdp8 -lm -lrt -lpthread -lpcre2-8 -ldl -ledit -ltermcap -lpng -lz
BIN/pdp8 RegisterSanityCheck /mnt/e/Users/Mark/source/download/open-simh/PDP8/tests/pdp8_test.ini </dev/null
Running internal register sanity checks on PDP-8 simulator.
*** Good Registers in PDP-8 simulator.

PDP-8 simulator Open SIMH V4.1-0 Current        git commit id: a1f57fa3
** PDP-8: Basic Instruction Test (1): passed
** PDP-8: Basic Instruction Test (2): passed
** PDP-8: Adder tests:

SIMAD
SIMROT
FCT
RANDOM


*******7 EXTENDED BANKS OF MEMORY TO BANK 1*******


** PDP-8: Adder test passed.
** PDP-8: Random AND test: passed.
** PDP-8: Random TAD test: passed.
** PDP-8: Random ISZ test:

FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
** PDP-8: Random ISZ test: passed.
** PDP-8: Random DCA test: passed.

!! All Tests Passed !!

mark@Ubuntu-26.04:$

BTW, Trixie is NOT a Ubuntu release, but a Debian one.

I might look at what is going on IF you provide all of the inputs that are referenced in your ini file.

Additionally you should provide the output that is produced when you build your pdp8 simulator.

[markpizz]

Also on the latest Debian on a Raspberry Pi-5, I get this build:

mark@Pi-5:~/open-simh $ make pdp8
lib paths are: /lib/ /lib/aarch64-linux-gnu/ /usr/lib/aarch64-linux-gnu/libfakeroot/ /usr/lib/
include paths are:  /usr/lib/gcc/aarch64-linux-gnu/14/include /usr/local/include /usr/include/aarch64-linux-gnu /usr/include
using libm: /lib/aarch64-linux-gnu/libm.so
using librt: /lib/aarch64-linux-gnu/librt.a
using libpthread: /lib/aarch64-linux-gnu/libpthread.a /usr/include/pthread.h
using libpcre2-8: /lib/aarch64-linux-gnu/libpcre2-8.so /usr/include/pcre2.h
using semaphore: /usr/include/semaphore.h
using libdl: /lib/aarch64-linux-gnu/libdl.a /usr/include/dlfcn.h
using libedit: /usr/include/editline/readline.h
using libpng: /lib/aarch64-linux-gnu/libpng.so /usr/include/png.h
using zlib: /lib/aarch64-linux-gnu/libz.so /usr/include/zlib.h
using mman: /usr/include/aarch64-linux-gnu/sys/mman.h
using libSDL2: /usr/include/SDL2/SDL.h
*** No SDL ttf support available.  BESM-6 video panel disabled.
***
*** Info *** Install the development components of libSDL2-ttf
*** Info *** packaged for your Linux operating system distribution:
*** Info ***        $ sudo apt-get install libsdl2-ttf-dev
***
*** pdp8 Simulator being built with:
*** - compiler optimizations and no debugging support. GCC Version: 14.2.0.
*** - video capabilities provided by libSDL2 (Simple Directmedia Layer).
*** - Per simulator tests will be run.
***
*** git commit id is a1f57fa3738ed31148d31126ba1a7278ff845c6d.
*** git commit time is 2026-07-03T13:48:11+0200.
***
gcc -std=gnu99 -U__STRICT_ANSI__  -O2 -DNDEBUG=1 -finline-functions -fgcse-after-reload -fpredictive-commoning -fipa-cp-clone -fno-unsafe-loop-optimizations -fno-strict-overflow -DSIM_GIT_COMMIT_ID=a1f57fa3738ed31148d31126ba1a7278ff845c6d -DSIM_GIT_COMMIT_TIME=2026-07-03T13:48:11+0200  -DSIM_COMPILER="GCC Version: 14.2.0" -DSIM_BUILD_TOOL=simh-makefile -I . -Werror -D_GNU_SOURCE -DHAVE_PCRE2_H -DHAVE_SEMAPHORE -DHAVE_SYS_IOCTL -DHAVE_LINUX_CDROM -DSIM_HAVE_DLOPEN=so -DHAVE_EDITLINE -DHAVE_UTIME -DHAVE_LIBPNG -DHAVE_ZLIB -DHAVE_GLOB -DHAVE_SHM_OPEN  ./PDP8/pdp8_cpu.c ./PDP8/pdp8_clk.c ./PDP8/pdp8_df.c ./PDP8/pdp8_dt.c ./PDP8/pdp8_lp.c ./PDP8/pdp8_mt.c ./PDP8/pdp8_pt.c ./PDP8/pdp8_rf.c ./PDP8/pdp8_rk.c ./PDP8/pdp8_rx.c ./PDP8/pdp8_sys.c ./PDP8/pdp8_tt.c ./PDP8/pdp8_ttx.c ./PDP8/pdp8_rl.c ./PDP8/pdp8_tsc.c ./PDP8/pdp8_td.c ./PDP8/pdp8_ct.c ./PDP8/pdp8_fpp.c ./PDP8/pdp8_dpy.c ./display/display.c ./display/sim_ws.c ./scp.c ./sim_console.c ./sim_fio.c ./sim_timer.c ./sim_sock.c ./sim_tmxr.c ./sim_ether.c ./sim_tape.c ./sim_disk.c ./sim_serial.c ./sim_video.c ./sim_imd.c ./sim_card.c -I ./PDP8 -DUSE_DISPLAY -DHAVE_LIBSDL -DUSE_SIM_VIDEO `sdl2-config --cflags` `sdl2-config --libs` -o BIN/pdp8 -lm -lrt -lpthread -lpcre2-8 -ldl -ledit -ltermcap -lpng -lz
BIN/pdp8 RegisterSanityCheck /home/mark/open-simh/PDP8/tests/pdp8_test.ini </dev/null
 Running internal register sanity checks on PDP-8 simulator.
*** Good Registers in PDP-8 simulator.

PDP-8 simulator Open SIMH V4.1-0 Current        git commit id: a1f57fa3
** PDP-8: Basic Instruction Test (1): passed
** PDP-8: Basic Instruction Test (2): passed
** PDP-8: Adder tests:

SIMAD
SIMROT
FCT
RANDOM


*******7 EXTENDED BANKS OF MEMORY TO BANK 1*******


** PDP-8: Adder test passed.
** PDP-8: Random AND test: passed.
** PDP-8: Random TAD test: passed.
** PDP-8: Random ISZ test:

FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
FC
** PDP-8: Random ISZ test: passed.
** PDP-8: Random DCA test: passed.

!! All Tests Passed !!

mark@Pi-5:~/open-simh 

[markpizz]

There is absolutely no mention of libpcre3 in the github.com/open-simh/simh code or makefile.

From that, I'm guessing that you, in fact are actually using an much older version of simh from the github.com/simh/simh repository which indeed had reference to libpcre3.

The latest code in github.com/simh/simh repository builds cleanly on Trixie on a Raspberry-Pi (and Ubuntu 26.04 in WSL) and has full functionality with the code and commands that use PCRE. No reference to any PCRE commands were mentioned in your pdp8.ini file, so without any of those commands it is hard to imagine how you might come to blame PCRE.

If, you problem is really related to use of code from github.com/simh/simh, you should create a issue in that repository to get it resolved.