FreeBasic Unlike QuickBASIC

[dodicat]

I suppose Munair, that had it worked and had you wanted to change a name sometime in the imaginary future, then you would have had to change the offset name also.
But it doesn't work so you have been spared the pain of recommending it in that imaginary future.

[Munair]

I suppose Munair, that had it worked and had you wanted to change a name sometime in the imaginary future, then you would have had to change the offset name also.
But it doesn't work so you have been spared the pain of recommending it in that imaginary future.

OK, well I just looked at the snippet but didn't test it.

[Munair]

I use FreeBASIC for over a year now (not counting some tries in earlier years) and at this point the overall FEEL I get compared to QuickBASIC in particular, is that while FreeBASIC's keywords are practically the same, some important features, most notably pointers and their syntax, make it much more C like. FreeBASIC is powerful and unlike QuickBASIC, you need to know what you're doing; there are less safe guards in place so to speak, and it is relatively easy to get a *** stack smashing detected *** crash as this (illogical) example demonstrates:

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type Typed64Bits
    value as string * 8
end type

type TypedLongInt
    value as longint
end type

function LongIntBStr(byval value as longint) as string
	dim n as TypedLongInt
	dim s as Typed64Bits
	n.value = value
	lset s = n
	return *cptr(string ptr, @(s.value))
end function

function LongIntBVal(byval value as string) as longint
	dim s as Typed64Bits
	dim n as TypedLongInt
	s.value = value
	lset n = s
	return n.value
end function

' TESTING
dim as longint v1 = rnd * 9223372036854775807
dim as string s1 = LongIntBStr(v1)
	print LongIntBVal(s1) 

end

A recent less obvious issue found by dodicat, is another illogical statement that invokes a kind of forward declaration (might be a bug):

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dim as string x=string(len(x),"?")
print x
print len(x)
sleep

These examples are not meant to downgrade FreeBASIC in any way. It just tells one to be careful and to know exactly what you're doing. In contrast, I think the worst errors I got in QuickBASIC (if I remember correctly) were memory related, like stack overflow with recursion and out of memory with large arrays on the heap.
Bottomline, FreeBASIC looks a lot like QuickBASIC but that's only on the outside.

[fxm]

By cons, the dynamic version (using New) of your second example works:

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dim as string ptr ps = new string(string(len(*ps),"?"))
print *ps
print len(*ps)
sleep

[Munair]

By cons, the dynamic version (using New) of your second example works:

Code: Select all

dim as string ptr ps = new string(string(len(*ps),"?"))
print *ps
print len(*ps)
sleep

Yes, it also correctly gives a warning upon compilation:

fixed1.c: In function ‘main’:
fixed1.c:34:15: warning: ‘PS$0’ may be used uninitialized in this function [-Wmaybe-uninitialized]
int64 vr$3 = fb_StrLen( (void*)PS$0, -1ll );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Compilation finished successfully.

At least the same warning should be given with the previous syntax, IMO.

[fxm]

Works with gas (32-bit), warns and crashes with gcc (32&64-bit).

[Munair]

I just compiled with -w all

[fxm]

I just compiled with -w all

in 64-bit?

[Munair]

I just compiled with -w all

in 64-bit?

Yes, Manjaro Linux and a recent built (1.06)

[fxm]

64-bit => always gcc.

[Munair]

64-bit => always gcc.

But no crash.

[fxm]

The compilation gcc crashes on my PC (Win10).

[Munair]

The compilation gcc crashes on my PC (Win10).

Not on Linux apparently. See the warning message: "Compilation finished successfully."

[srvaldez]

The compilation gcc crashes on my PC (Win10).

what version of FB and gcc are you using?
I tried the following and both compile with the warning
FreeBASIC-1.06.0-win64\fbc -w all -asm intel -gen gcc -Wc -O2 -v "%f"

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untitled10.c: In function 'main':
untitled10.c:33:15: warning: 'PS$0' is used uninitialized in this function [-Wuninitialized]
  int64 vr$3 = fb_StrLen( (void*)PS$0, -1ll );
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Compilation finished successfully.

Code: Select all

FreeBASIC Compiler - Version 1.06.0 (05-07-2017), built for win64 (64bit) standalone
gcc.exe (x86_64-win32-seh, Built by MinGW-W64 project) 4.8.2

FreeBASIC Compiler - Version 1.06.0 (08-26-2018), built for win64 (64bit) standalone
gcc.exe (x86_64-win32-seh-rev0, Built by MinGW-W64 project) 8.1.0

please also show your compile command

[fxm]

The compilation gcc crashes on my PC (Win10).

Excuse me:
The 'exe' file compiled with gcc crashes on my PC (Win10).