Testing the 'bad subscript' error - did not expect this

[Bumblebee]

Code Select Expand

dim b(1 to 5) as string
print lbound(b)
print ubound(b)
print "Press any key to continue..."
sleep
print b(8)
print "Press any key to quit"
sleep
endInstead of a program crash, generates some gibberish, then runs the next lines of code.

Compiler log file:
Successful Compile (Errors 0 Warnings 0)

Primary Source: C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\Untitled1.bas
Target Compilation: C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\Untitled1.exe (29 KB, 29696 bytes)
Compile Time: 0.0 seconds (2023-11-25 09:04:03)

Command Line:
C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\fbc32.exe -m "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\Untitled1.bas" -v -s console  -x "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\Untitled1.exe"

FreeBASIC Compiler - Version 1.07.2 (2020-12-25), built for win32 (32bit)
Copyright (C) 2004-2019 The FreeBASIC development team.
standalone
target:       win32, 486, 32bit
compiling:    C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\Untitled1.bas -o C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\Untitled1.asm (main module)
assembling:   C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\bin\win32\as.exe --32 --strip-local-absolute "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\Untitled1.asm" -o "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\Untitled1.o"
linking:      C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\bin\win32\ld.exe -m i386pe -o "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\Untitled1.exe" -subsystem console "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\lib\win32\fbextra.x" --stack 1048576,1048576 -s -L "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\lib\win32" -L "." "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\lib\win32\crt2.o" "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\lib\win32\crtbegin.o" "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\lib\win32\fbrt0.o" "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\Untitled1.o" "-(" -lfb -lgcc -lmsvcrt -lkernel32 -luser32 -lmingw32 -lmingwex -lmoldname -lgcc_eh "-)" "C:\ProgramData\WinFBE\FreeBASIC-1.07.2-gcc-5.2\lib\win32\crtend.o"

[Bumblebee]

Print b(32) is more interesting - partial gibberish followed by a crash 

[Paul Squires]

Yup, you're reading memory from outside the range of the array. Heaven knows what you will print.   

BTW, you can catch these types of out of bounds situations by enabling the -exx compile flag (array bound sand null pointer check). You can find that flag in WinFBE's Build Configurations.

[Bumblebee]

Okay, I will enable it.

Do you know why multiples of 8 are causing these printouts to console?