Sven Barth via fpc-devel wrote:
I doubt that records larger than say 4 register widths are ever passed
by-value. But I definitely can't exclude it, cause I don't know every
ABI of every platform by heart. So if you want details there then study
the ABIs of the platforms you use.
I doubt that
Adriaan van Os via fpc-devel schrieb am
Do., 2. Feb. 2023, 02:47:
> Sven Barth via fpc-devel wrote:
>
> > There is no full documentation for that parameter modifier (someone
> > might want to file a bug report for that), but the documentation for
> > “const” (
> >
> https://www.freepascal.org/doc
Am 02.02.2023 um 02:09 schrieb Hairy Pixels:
On Feb 2, 2023, at 4:38 AM, Sven Barth wrote:
Which types are passed by-value or by-reference when using const is determined
by the size of the record and the types of the fields based on whatever the
corresponding ABI defines (e.g. the x86_64 Sy
> On Feb 2, 2023, at 8:41 AM, Adriaan van Os via fpc-devel
> wrote:
>
> On debate, see FPC issue 17442.
https://gitlab.com/freepascal.org/fpc/source/-/issues/17442
Yes this is what I remember learning.
What I think should be documented is what you should do for records that over a
certain
Hairy Pixels via fpc-devel wrote:
On Feb 2, 2023, at 4:38 AM, Sven Barth wrote:
Which types are passed by-value or by-reference when using const is determined
by the size of the record and the types of the fields based on whatever the
corresponding ABI defines (e.g. the x86_64 Sys V ABI is
Sven Barth via fpc-devel wrote:
There is no full documentation for that parameter modifier (someone
might want to file a bug report for that), but the documentation for
“const” (
https://www.freepascal.org/docs-html/current/ref/refsu67.html#x183-20700014.4.4
) contains this:
=== doc begin =
> On Feb 2, 2023, at 4:38 AM, Sven Barth wrote:
>
> Which types are passed by-value or by-reference when using const is
> determined by the size of the record and the types of the fields based on
> whatever the corresponding ABI defines (e.g. the x86_64 Sys V ABI is rather
> explicit about s
On Wed, 1 Feb 2023, Sven Barth via fpc-devel wrote:
Am 01.02.2023 um 11:30 schrieb Bart via fpc-devel:
I thought that constref would be OK for that (the word constref
suggests to me tah the paramter will be treated (by me) to be a
constant, and that it shall be passed by reference in all case
Am 01.02.2023 um 11:30 schrieb Bart via fpc-devel:
I thought that constref would be OK for that (the word constref
suggests to me tah the paramter will be treated (by me) to be a
constant, and that it shall be passed by reference in all cases,
whereas with a const parameter the compiler decides u
Am 01.02.2023 um 15:40 schrieb Hairy Pixels via fpc-devel:
On Feb 1, 2023, at 8:27 PM, Michael Van Canneyt via fpc-devel
wrote:
That's exactly what Adriaan is saying. With const the compiler can choose.
With constref, you force it not to copy. But this is not so efficient for
small parameter
On 2023-02-01 15:40, Hairy Pixels via fpc-devel wrote:
On Feb 1, 2023, at 8:27 PM, Michael Van Canneyt via fpc-devel
wrote:
That's exactly what Adriaan is saying. With const the compiler can
choose.
With constref, you force it not to copy. But this is not so efficient
for
small parameter si
On Wed, 1 Feb 2023, Hairy Pixels via fpc-devel wrote:
On Feb 1, 2023, at 8:27 PM, Michael Van Canneyt via fpc-devel
wrote:
That's exactly what Adriaan is saying. With const the compiler can choose.
With constref, you force it not to copy. But this is not so efficient for
small parameter
> On Feb 1, 2023, at 8:27 PM, Michael Van Canneyt via fpc-devel
> wrote:
>
> That's exactly what Adriaan is saying. With const the compiler can choose.
> With constref, you force it not to copy. But this is not so efficient for
> small parameter sizes.
So const will always pass records that a
On Wed, 1 Feb 2023, Hairy Pixels via fpc-devel wrote:
On Feb 1, 2023, at 8:16 PM, Adriaan van Os via fpc-devel
wrote:
Because, if e.g. the byte-size of a parameter is such that it fits into a CPU
register, then passing the parameter itself is more efficient than passing a
reference to
> On Feb 1, 2023, at 8:16 PM, Adriaan van Os via fpc-devel
> wrote:
>
> Because, if e.g. the byte-size of a parameter is such that it fits into a CPU
> register, then passing the parameter itself is more efficient than passing a
> reference to it. For large byte-size parameters, const and co
Hairy Pixels via fpc-devel wrote:
On Feb 1, 2023, at 5:56 PM, Adriaan van Os via fpc-devel
wrote:
"A const parameter is be passed by reference or (for small-sized parameters) by
value, whatever is most efficient. A constref parameter is guaranteed to be passed by
reference in all cases. Th
> On Feb 1, 2023, at 5:56 PM, Adriaan van Os via fpc-devel
> wrote:
>
> "A const parameter is be passed by reference or (for small-sized parameters)
> by value, whatever is most efficient. A constref parameter is guaranteed to
> be passed by reference in all cases. The latter is therefore ty
On Wed, Feb 1, 2023 at 11:56 AM Adriaan van Os via fpc-devel
wrote:
> That is wrong. It should read
>
> "A const parameter is be passed by reference or (for small-sized parameters)
> by value, whatever is
> most efficient. A constref parameter is guaranteed to be passed by reference
> in all ca
Bart via fpc-devel wrote:
"Note that in general, it should only be used for interfacing with
external code or when writing assembler routines."
That is wrong. It should read
"A const parameter is be passed by reference or (for small-sized parameters) by value, whatever is
most efficient. A c
Hi,
I have a function that has a parameter to a datastructure with some
arrays with records is it.
This function needs to return a pointer to a specific record inside
that structure.
The function is not supposed to alter the contents of this datastructure.
So, I need to pass this structure by refe
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