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A quick question about library and shortstrings
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Topic: A quick question about library and shortstrings (Read 451 times)
cdbc
Hero Member
Posts: 1025
A quick question about library and shortstrings
«
on:
September 24, 2022, 11:24:03 am »
Hi
Instead of using pchars in library funcrions, is it possible to use shortstrings e.g.
Code: Pascal
[Select]
[+]
[-]
type
TStr80
=
string
[
80
]
;
...
1
)
Function
libGetVersion
(
hObj
:
ptruint
)
:
pchar
;
cdecl
;
// works fine
2
)
Function
libGetVersion
(
hObj
:
ptruint
)
:
shortstring
;
cdecl
;
// ?!?
3
)
Function
libGetVersion
(
hObj
:
ptruint
)
:
TStr80
;
cdecl
;
// ?!?
Would 2 or 3 be ok?
Regards Benny
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If it ain't broke, don't fix it
PCLinuxOS(rolling release) 64bit -> KDE5 -> FPC 3.2.2 -> Lazarus 2.2.6 up until Jan 2024 from then on it's: KDE5/QT5 -> FPC 3.3.1 -> Lazarus 3.0
Thaddy
Hero Member
Posts: 14197
Probably until I exterminate Putin.
Re: A quick question about library and shortstrings
«
Reply #1 on:
September 24, 2022, 11:29:40 am »
1. works fine for string[255]
Anyway it is better to use Pchar, unless you know for sure the library is Pascal and you use it ONLY from Pascal.
And make sure you do not rely on Pascal's memory management.
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Specialize a type, not a var.
marcov
Administrator
Hero Member
Posts: 11382
FPC developer.
Re: A quick question about library and shortstrings
«
Reply #2 on:
September 24, 2022, 11:53:39 am »
If the other side can be made to understand it, then yes. shortstring is a normal static type like a fixed array.
shortstring without [] is equal to shortstring[255]
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cdbc
Hero Member
Posts: 1025
Re: A quick question about library and shortstrings
«
Reply #3 on:
September 24, 2022, 12:48:28 pm »
Hi
Thank you both
I'm in control of both the library(*.so) and the app... I was just curious
Regards Benny
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If it ain't broke, don't fix it
PCLinuxOS(rolling release) 64bit -> KDE5 -> FPC 3.2.2 -> Lazarus 2.2.6 up until Jan 2024 from then on it's: KDE5/QT5 -> FPC 3.3.1 -> Lazarus 3.0
marcov
Administrator
Hero Member
Posts: 11382
FPC developer.
Re: A quick question about library and shortstrings
«
Reply #4 on:
September 24, 2022, 01:24:36 pm »
Note that the problem with shortstrings is obviously the length limitation.
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