Re: Is there some way of calling a system command?

["Michel Simeon" <michel.simeon1@free.fr>]

I am learning Ada and does not know C.
I tried your approach to call an othe program from Ada and it worked, except 
for one problem: the calling program will wait for the return parameter (Rc 
in your exemple) and thus freeze till the other one is closed.
Could i do something similar but withour the retrun parameter ?

-- 
Michel Simeon

<jimmaureenrogers@worldnet.att.net> wrote in message 
news:1150031952.347657.244910@i40g2000cwc.googlegroups.com...
> Aldebaran wrote:
>> I am a newbie Ada-programmer and need help with this topic.
>> In C one can launch a system command, for instance through
>>  the following function.
>>
>>  system("ls ");
>>
>> or in JAVA
>>
>>  exec("ls");
>>
>> Is there some similar  way of calling a system command in ADA?
>
> The easiest way is to simply call the C system command.
> The example below was run on my Windows XP system.
>
> with Interfaces.C.Strings;
> use Interfaces.C.Strings;
>
> procedure System_Example is
>   function System_Call(Command : Chars_Ptr) return Interfaces.C.Int;
>   pragma Import(Convention => C, Entity => System_Call,
>      External_Name => "system");
>   Rc : Interfaces.C.Int;
>
> begin
>   Rc := System_Call(New_String("dir"));
>
> end System_Example;
>
> The important part of the example is the creation of a function
> specification I have named System_Call. That function specification
> take a parameter of Chars_Ptr, which corresponds to a C char *.
> The function specification is used as the Ada interface to the C
> system call. The compiler is notified of that association through
> the pragma Import. That pragma causes the compiler to link the C
> system command and call it whenever System_Call is called in the
> Ada code.
>
> Jim Rogers
>