Re: Format string bugs & race conditions

[Marius Amado Alves <amado.alves@netcabo.pt>]

> /*  If lockfile already exists, wait until it goes away.  */
> while((p = fopen("lockfile", "r"))) {
>     fclose(p);
>     sleep(1);
> }
> /*  (race)  */
> p = fopen("lockfile", "w");
> /*  Access the stuff which lockfile is supposed to protect from
>  *  multiple access.  But of course it doesn't.  */
> fclose(p);
> remove("lockfile");
> 
> Ada just makes it easier to implement this bug within a single
> instance of the executable.

No. Using files for locks is equally easy to implement and equally buggy 
in any language. But in Ada you would implement a lock as a protected 
object and be safe from race conditions by definition.

Regarding format strings my experience confirms that the C approach is 
buggy and Ada is not. In Ada you can format even better than in C and 
very safely even without leaving the standard. Resources include: Put 
and Get procedures for all scalar types, all bases; actual format 
strings, COBOL picture strings, in Annex F; the 'Image attribute, handy 
for quick instrumentation. Happy formating :-)