EXTENSIONS IN MY OS

[nuno_silva_pt]

Can anyone please tell me how i can make a OS recognize the extension (APP) as an executable?

[Pype.Clicker]

you mean something like when typing "edit" at a shell, the system will know that it should execute "edit.app" ?

Most systems use the notion of PATH variable, which gives the shell a list of directories where programs may exists. if you're requested to execute "edit", your shell will

Code: Select all

foreach $directory in (PATH) {
    if ($command.app in $directory) {
       $program = $directory/$command.app;
       break;
    }
}

if (!$program) complain("command not found");
else exec($program);

Note that under unix, this is preferred to be a 'access right bit' rather than an extension prefix. Wheter one or the other is selected is simply a matter of taste, but i guess the 'executable bit' is easier to program with ... Making it a part of the filename is somehow ... hackish imho ...

Now maybe your question is rather "how can i load the .APP file in memory so that i can execute it" ? ... in which case reading "Linkers and Loader" e-book will certainly be a wise idea

[nuno_silva_pt]

you mean something like when typing "edit" at a shell, the system will know that it should execute "edit.app" ?

That's not quite that.

Now maybe your question is rather "how can i load the .APP file in memory so that i can execute it" ? ... in which case reading "Linkers and Loader" e-book will certainly be a wise idea

Yes, that is the question!

Most systems use the notion of PATH variable, which gives the shell a list of directories where programs may exists. if you're requested to execute "edit", your shell will

Code: Select all

foreach $directory in (PATH) {
    if ($command.app in $directory) {
       $program = $directory/$command.app;
       break;
    }
}

if (!$program) complain("command not found");
else exec($program);

Can you write that in c please?
Thank you for your help!

[proxy]

no offense, but you really should be able to convert psuedo code to C code (especially somthing that simple).

Anyway, it wont translate directly to C because he is using the notion of "foreach" which basically says give me an iterator for each item in this container. C has no containers, and even if we assume it is a struct or somthing, you'd have to make many assumptions on the organization of the data. His code was simply a demonstration of the concept. FInally the line:

Code: Select all

if ($command.app in $directory) {

is going to to be very dependant on YOUR particular file system implementation.

good luck, but I recomend you do a bit mroe reading and general C programming before diving into an OS, it is not for the faint hearterd.

If I am wrong about your experience, then I appologize and once again, good luck.

proxy

[Pype.Clicker]

no. i cannot ... actually, i can, but only if you have the same C library which i assume you have, which is probably not the case. So my C code would be useless and more difficult to understand.