How can I get the current time in microseconds (formatted as integer64) in ada ?

I want to get the equivalent of C function clock_gettime (frome time.h).

I want to create a library taking a kind of generic type (or something like this, I don't know how it is called).

What I have :

package A is
    type A_Type is record
        Field : Field_Type;
        A_Access : access A;
    end record;
end A;

package B is
    type B_Type is record
        OtherField : OtherField_Type;
        B_Access : access B;
    end record;
end B;

I want to create a common library taking A_Type or B_Type as parameters. My library cannot include A or B. It will be something like :

package CommonLib is
    procedure DoStuff (Param : Generic_Type);
end CommonLib;

-- Can be used by A :
A : A_Type;
CommonLib.DoStuff(A);

-- Can be used by B :
B : B_Type;
CommonLib.DoStuff(B);

How can I do ?

I want to import a C function in Ada.

There is the C part :

void Register(const void *ctxt)
{
   saved_ctxt = ctxt; // This is a global variable 
}

void Send_Trace(const void *ctxt,
                const char *msg)
{
    if (saved_ctxt == ctxt)
    {
        // Do stuff with msg
    }
}

Now I want to use this function in a Ada program. There is my code :

type T_void is tagged null record;
package C renames Interfaces.C;

procedure Send_Trace_From_C(ctxt : in T_void;
                            msg  : in String)
is
    pragma Convention(C, T_void);

    procedure send_trace (A: out T_void; B : C.Strings.char_ptr);
    pragma import (C, Send_Trace, "Send_Trace");

    Char_ptr : C.Strings.char_ptr := C.Strings.New_String(msg);
begin
    send_trace (ctxt, Char_ptr);
end Send_Trace_From_C;

But I have errors :

pragma "convention" argument must be in same declarative part

warning "send_trace" involves a tagged type which does not correspond to any C type

How can I use a *void in Ada ?

I'm using a library in ada which contains many types :

type Int8 is range -8 ** 7 .. 2 ** 7 - 1;
subtype T_Name_String is Int8;
type T_Name_String_Fixed20 is array (range 1..20) of T_Name_String ;

And there is a record with :

type The_Record is record
   name : T_Name_String_Fixed20;
   -- and others
end record;

I can't change that, I don't know why there are using Int8 for ada strings but I'm not able to initiate the field name. I've try :

-- First try:
MyRecord.name = "hello               ";
-- Error : expected type T_Name_String_Fixed20 found a string type

-- Second try
Ada.Strings.Fixed.Move(Target => MyRecord.name;
                       Source => "hello               "

There seem to be two different ways to do the same thing when using the AUnit library:

Using the AUnit.Test_Cases.Test_Case type, creating some function tests, then register each tests with the AUnit.Test_Cases.Register_Tests function. We can then add this Test_Case to a Suite using the function AUnit.Test_Suites.Add_Test.

There some example of this:

• the example of the cookbook
• this SO answer
• in the unit test of AdaYaml

(Surprisingly, there no examples using this way in the AUnit repository.)

The other way is to use the AUnit.Test_Fixtures.Test_Fixture type, creating some function tests. These tests can then be added to a Suite using the generic package AUnit.Test_Caller with the functions AUnit.Test_Suites.Add_Test and AUnit.Test_Caller.Create.

I can see way of using Test_Caller in:

• the example of the cookbook
• the examples AUint repo
• in the unit test of json-ada

The only difference I can see is that, when using the AUnit.Test_Cases.Test_Case, you can override the Set_Up_Case, Set_Up, Tear_Down and Tear_Down_Case functions. While with the AUnit.Test_Fixtures.Test_Fixture you can only override the Set_Up and Tear_Down functions (because the tests are not group under a Test_Case).

Appart from that, I don't really see much difference.

So, what is the use of the AUnit.Test_Fixtures.Test_Fixture type with the generic package AUnit.Test_Caller ? Why would use this over the (simpler ?) AUnit.Test_Cases.Test_Case type ?

Every example I have seen in one format can be transformed into the other (the Set_Up_Case and Tear_Down_Case set appart). Could give an example which use one but cannot be done by the other ?

I have a File_Reader composed of two records, File and Buffer. I would like to ensure both Records always have a valid buffer size when initialized, i.e. Data_File.IO_Buffer_Size is equal to Data_In.Size.

I couldn't find a way of initializing a record component's value with another record's component value or discriminant, so I figured I would at least apply a static predicate which was unsuccessful. Using dynamic predicate as,an alternative poses issues in a LightRuntime environment.

I could easily add a Buffer_Size discriminant to File_Reader, but I would like to explore alternative solutions. Lastly, the record layouts must be preserved since they are memory mapped using representation clauses which are not shown:

type File is 
   record
      Name           : String;
      IO_Buffer_Size : Buffer_Size;
   end record; 

type Buffer(Size : Buffer_Size := 300)  is         
   record
      Pos   : Buffer_Size := 0;
      Value : String(1 .. Size);
   end record;

type File_Reader(Name : String) is 
   record        
       Data_In      : Buffer;    
       Data_File    : File := (Name, Data_In.Size); -- Won't work
   end record;

OBS! My code is written with Swedish terms.

I have to code a VAT table but i have run in to some problems concerning Floats and the way that it rounds values. At first, I was using a while loop but that didn't work since it (after a while) got too affected by the float-issue.

I created a For-loop instead which in theory should work better. However. I'm having an issue with one of my variables.

The variable "Antal_Rader" is being declared before the For-loop but i still get the error code: "object "Antal_rader" cannot be used before end of its declaration"

Code:

with Ada.Text_IO;              use Ada.Text_IO;
with Ada.Float_Text_IO;        use Ada.Float_Text_IO;

procedure Momstabellen is
   Forsta_Pris : Float;
   Sista_Pris : Float;
   Steglangd : Float;
   Momsprocent : Float;
   Moms : Float;
   Antal_Rader : Float;
   Nuvarande_Rad : Float;
   
   
begin
   -- 1. Ta emot alla variabler för momstabellen:
   Put("Första pris: ");
   Get(Forsta_Pris);
   while Forsta_Pris < 0.0 loop
      Put("Felaktigt värde!");
      New_Line;
      Put("Första pris: ");
      Get(Forsta_Pris);
    end loop;
   
   Put("Sista pris: ");
   Get(Sista_Pris);
   while Sista_Pris < Forsta_Pris loop
      Put("Felaktigt värde!");
      New_Line;
      Put("Sista pris: ");
      Get(Sista_Pris);
   end loop;
   
   Put("Steg: ");
   Get(Steglangd);
   while Steglangd < 0.0 loop
      Put("Felaktigt värde!");
      New_Line;
      Put("Steg: ");
      Get(Steglangd);
   end loop;
   
   Put("Momsprocent: ");
   Get(Momsprocent);
   while Momsprocent < 0.0 or Momsprocent > 100.0 loop
      Put("Felaktigt värde!");
      New_Line;
      Put("Momsprocent: ");
      Get(Momsprocent);
   end loop;
   New_Line;

-- 2. Skapa en layout för momstabellen:
   Put("============ Momstabell ============");
   New_Line;
   Put("Pris utan moms  Moms   Pris med moms");
   New_Line;

Issue lies here:

   

   Antal_Rader := (Sista_Pris - Forsta_Pris)/Steglangd;
   
   for I in 0 .. Antal_Rader loop
      
      Nuvarande_Rad := Antal_Rader * Steglangd + Forsta_Pris;   
      Moms := Nuvarande_Rad/100.0 * Momsprocent;
      
      Put(Nuvarande_Rad, Fore=> 6, Aft => 2, Exp => 0);
      Put(Moms, Fore => 8, Aft => 2, Exp => 0);
      Put(Nuvarande_Rad + Moms, Fore => 9, Aft => 2, Exp => 0);
     
   end loop;
    
     
end Momstabellen;

I have tried changing the first line of the For-loop and also tried changing the position of "Antal_Rader" but nothing has worked.

I am quite new to this so i can't think of many more things to do.

Note for subscribers: if you are interested in my Ada programming articles only, you can use this RSS feed link.

Spot the "tool tip" on the following screenshot...

Click to enlarge

Translation: cross-references and source code navigation in LEA are becoming a reality since this evening!

Some Web links:

LEA

Web site: http://l-e-a.sf.net/
Sources, site #1: https://sf.net/p/l-e-a/code/HEAD/tree/
Sources, site #2: https://github.com/zertovitch/lea
Alire Crate: Alire - LEA

Since LEA embeds the HAC compiler, here are a few links about HAC as well:

HAC

Web site: https://hacadacompiler.sourceforge.io/
Sources, site #1: https://sf.net/p/hacadacompiler/code/HEAD/tree/
Sources, site #2: https://github.com/zertovitch/hac
Alire Crate: Alire - HAC

I am trying to get gnatcoll_postgres into C:\GNColl_Postgresql using Alire on Windows 10. But the process failed while installing mingw-w64-x86_64-postgresql.

The errors message are as follows:

error: mingw-w64-x86_64-mpc: signature from "David Macek <[email protected]>" is unknown trust
:: File /var/cache/pacman/pkg/mingw-w64-x86_64-mpc-1.2.1-1-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]
error: mingw-w64-x86_64-bzip2: signature from "David Macek <[email protected]>" is unknown trust
:: File /var/cache/pacman/pkg/mingw-w64-x86_64-bzip2-1.0.8-2-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]
error: mingw-w64-x86_64-termcap: signature from "David Macek <[email protected]>" is unknown trust
:: File /var/cache/pacman/pkg/mingw-w64-x86_64-termcap-1.3.1-6-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]
error: failed to commit transaction (invalid or corrupted package)
Errors occurred, no packages were upgraded.
ERROR: Deployment of system package from platform software manager: mingw-w64-x86_64-postgresql to C:\GNColl_Postgresql\gnatcoll_postgres_23.0.0_adf8e40f\alire\cache\dependencies\postgresql_15.1.0_system failed

Any idea on how to resolve this issue. Thanks in advance. Regards. Angelo.