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

[Per Sandberg <per.sandberg@sandat.dyndns.org>]

Why not just 
	GNAT.OS_Lib.spawn
or
	GNAT.Expect.*
?
/Persan


On Tue, 26 Nov 2013 07:35:26 -0800 (PST)
tolkamp <f.tolkamp@gmail.com> wrote:

> Op zondag 11 juni 2006 15:19:12 UTC+2 schreef
> jimmaure...@worldnet.att.net:
> > 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
> 
> Thank you for your reaction.
> For me this is not very understandable.
> Where must I put the directory path to the executable?
> Is this "dir" in  Rc := System_Call(New_String("dir"));?
>