Re: difference between

[Bruce Steers <bsteers4@xxxxxxxxx>]

Ps. Oops. Sorry that example code is not actually valid code.
Seems testing "If Not S1 Begins sSomething" will give "error expected
Boolean got String instead"

But the lesson is still there I think.

I HAVE had times where Not was being used in the wrong place in a
conditional statement in a similar way giving me wrong results, I just
picked String/Begins as a bad example I guess. It gives the correct message
but technically with invalid code.

BruceS

On Sat, 10 Oct 2026, 10:25 Bruce Steers, <bsteers4@xxxxxxxxx> wrote:

> I can possibly explain better with String and Begins...
> Consider this .
>
> s1 = ""
> s2 = "something"
>
> Now this
> If Not s1 Then Print "s1 has no text"
> If Not s2 Then Print "s2 has no text"
>
> Now look at this
> If Not s2 Begins "s" Then
>
> That is wrong and will return True only if s2 has no text, the 'Begins
> "s"' part is not tested at all.
> It is just the same as writing...
> If Not s2
>
> But this...
> If s2 Not Begins "s" Then
>
> That's correct Not is now testing if s2 Begins "s" and not just if s2 is
> Null
>
> Hope that is clearer for you 😎
> BruceS
>
> On Sat, 10 Oct 2026, 09:42 Bruce Steers, <bsteers4@xxxxxxxxx> wrote:
>
>> Not is only testing PictureBoxQRCode.Image, it ignores the = Null part
>>
>> Like
>> if Picturebox.Image Then
>> Or
>> if Not Picturebox.Image Then
>>
>> You must do like this...
>>  If PictureBoxQRCode.Image <> Null Then
>>
>> It just..
>>  If Not PictureBoxQRCode.Image Then
>>
>> BruceS
>>
>>
>> On Sat, 10 Oct 2026, 07:43 valaquarus, <valaquarus@xxxxxxxxx> wrote:
>>
>>> Hello,
>>> what are the differences between these two assertions, because they
>>> don't act exactly the same way :
>>>
>>> - If Not PictureBoxQRCode.Image = Null Then...
>>> - If Not IsNull(PictureBoxQRCode.Image) Then...
>>>
>>>
>>> [System]
>>> Gambas=3.22.99 2992226 (master)
>>> OperatingSystem=Linux
>>> Distribution=Manjaro Linux
>>> Kernel=7.2.3-2-MANJARO
>>> Architecture=x86_64
>>> Cores=4
>>> Memory=5713M
>>> Language=fr_FR.UTF-8
>>> Platform=x11
>>> Desktop=KDE
>>> DesktopResolution=96
>>> DesktopScale=9
>>> WidgetTheme=breeze
>>> Font=Adwaita Mono,12
>>> DarkTheme=False
>>> [Programs]
>>> appimage-builder=appimage-builder: 1.1.1.dev32+g2709a3b
>>> clang=clang version 22.1.8
>>> dpkg=Programme « dpkg » de gestion de paquets Debian version
>>> 1.23.7-dirty (amd64).
>>> gcc=gcc (GCC) 16.2.1 20260810
>>> git=git version 2.55.0
>>> msgmerge=msgmerge (GNU gettext-tools) 1.0
>>> pngquant=3.0.3
>>> rpmbuild=RPM version 6.0.1
>>> trans=Translate Shell 0.9.7.1-git:dc67af4
>>> [Libraries]
>>> Cairo=libcairo.so.2.11804.4
>>> Curl=libcurl.so.4.8.0
>>> DBus=libdbus-1.so.3.38.3
>>> GDK2=libgdk-x11-2.0.so.0.2400.33
>>> GDK3=libgdk-3.so.0.2420.32
>>> GStreamer=libgstreamer-1.0.so.0.2806.0
>>> GTK+2=libgtk-x11-2.0.so.0.2400.33
>>> GTK+3=libgtk-3.so.0.2420.32
>>> OpenGL=libGL.so.1.7.0
>>> Poppler=libpoppler.so.163.0.0
>>> QT5=libQt5Core.so.5.15.19
>>> QT6=libQt6Core.so.6.11.2
>>> RSvg=librsvg-2.so.2.62.3
>>> SDL=libSDL2-2.0.so.0.3200.72
>>> SQLite3=libsqlite3.so.3.53.4
>>> [Environment]
>>> DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
>>> DEBUGINFOD_URLS=https://debuginfod.archlinux.org
>>> DESKTOP_SESSION=/usr/share/xsessions/plasmax11.desktop
>>> DISPLAY=:0
>>> DOCKER_HOST=unix:///run/user/1000/podman/podman.sock
>>> GB_GUI=gb.gtk3
>>>
>>> GTK2_RC_FILES=/etc/gtk-2.0/gtkrc:<home>/.gtkrc-2.0:<home>/.config/gtkrc-2.0
>>> GTK_MODULES=canberra-gtk-module
>>> GTK_RC_FILES=/etc/gtk/gtkrc:<home>/.gtkrc:<home>/.config/gtkrc
>>> HOME=<home>
>>> ICEAUTHORITY=/run/user/1000/iceauth_IlqFFb
>>> INVOCATION_ID=41b15739ce1c46eb9a1566475fbf9362
>>> JOURNAL_STREAM=10:13404
>>> KDE_APPLICATIONS_AS_SCOPE=1
>>> KDE_FULL_SESSION=true
>>> KDE_SESSION_UID=1000
>>> KDE_SESSION_VERSION=6
>>> LANG=fr_FR.UTF-8
>>> LANGUAGE=fr_FR.UTF-8
>>> LOGNAME=<user>
>>> MAIL=/var/spool/mail/<user>
>>> MANAGERPID=826
>>> MANAGERPIDFDID=8436
>>>
>>> MEMORY_PRESSURE_WATCH=/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service
>>> /session.slice/plasma-plasmashell.service/memory.pressure
>>> MEMORY_PRESSURE_WRITE=c29tZSAyMDAwMDAgMjAwMDAwMAA=
>>> MOTD_SHOWN=pam
>>> OLDPWD=<home>
>>> PAM_KWALLET5_LOGIN=/run/user/1000/kwallet5.socket
>>>
>>> PATH=<home>/.local/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/var/lib/flatpak/exports/bin:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/usr/lib/rustup/bin
>>> PWD=<home>
>>> QT_LINUX_ACCESSIBILITY_ALWAYS_ON=1
>>> QT_LOGGING_RULES=*.debug=false
>>> QT_QPA_PLATFORM=xcb
>>>
>>> QT_SCREEN_SCALE_FACTORS=LVDS-1=1;VGA-1=1;HDMI-1=1;DP-1=1;HDMI-2=1;HDMI-3=1;DP-2=1;DP-3=1;
>>> QT_WAYLAND_RECONNECT=1
>>>
>>> SESSION_MANAGER=local/<hostname>:@/tmp/.ICE-unix/969,unix/<hostname>:/tmp/.ICE-unix/969
>>> SHELL=/usr/bin/zsh
>>> SYSTEMD_EXEC_PID=981
>>> TZ=:/etc/localtime
>>> USER=<user>
>>>
>>> VSSCRIPT_PATH=/usr/lib/python3.14/site-packages/vapoursynth/libvsscript.so
>>> XAUTHORITY=/run/user/1000/xauth_cjAxZJ
>>>
>>> XDG_CONFIG_DIRS=<home>/.config/kdedefaults:/etc/xdg:/usr/share/manjaro-kde-settings/xdg
>>> XDG_CURRENT_DESKTOP=KDE
>>>
>>> XDG_DATA_DIRS=<home>/.local/share/flatpak/exports/share:/var/lib/flatpak/exports/share:/usr/local/share:/usr/share
>>> XDG_MENU_PREFIX=plasma-
>>> XDG_RUNTIME_DIR=/run/user/1000
>>> XDG_SEAT=seat0
>>> XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
>>> XDG_SESSION_CLASS=user
>>> XDG_SESSION_DESKTOP=KDE
>>> XDG_SESSION_ID=2
>>> XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session1
>>> XDG_SESSION_TYPE=x11
>>> XDG_VTNR=2
>>>
>>>
>>> Good day to all of you
>>>
>>> --
>>>
>>> valaquarus <valaquarus@xxxxxxxxx>
>>>
>>