On Wed, Dec 07, 2011 at 03:25:48PM +0000, David Chisnall wrote: > Author: theraven > Date: Wed Dec 7 15:25:48 2011 > New Revision: 228322 > URL: http://svn.freebsd.org/changeset/base/228322 > > Log: > Implement quick_exit() / at_quick_exit() from C++11 / C1x. Also add a > __noreturn macro and modify the other exiting functions to use it. > > The __noreturn macro, unlike __dead2, must be used BEFORE the function. > This is in line with the C and C++ specifications that place _Noreturn (c1x) > and [[noreturn]] (C++11) in front of the functions. As with __dead2, this > macro falls back to using the GCC attribute. > > Unfortunately, clang currently sets the same value for the C version macro > in C99 and C1x modes, so these functions are hidden by default. At some > point before 10.0, I need to go through the headers and clean up the C1x / > C++11 visibility. > > Reviewed by: brooks (mentor) And, was it approved ?
> +#include <stdlib.h>
> +#include <pthread.h>
> +
> +/**
> + * Linked list of quick exit handlers. This is simpler than the atexit()
> + * version, because it is not required to support C++ destructors or
> + * DSO-specific cleanups.
> + */
> +struct quick_exit_handler {
> + struct quick_exit_handler *next;
> + void (*cleanup)(void);
> +};
> +
> +__attribute((weak))
> +void _ZSt9terminatev(void);
Why do you need this ?
You are not calling terminate() anyway, and added an explicit comment.
> +
> +/**
> + * Lock protecting the handlers list.
> + */
> +static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER;
> +/**
> + * Stack of cleanup handlers. These will be invoked in reverse order when
> + */
> +static struct quick_exit_handler *handlers;
> +
> +int
> +at_quick_exit(void (*func)(void))
> +{
> + struct quick_exit_handler *h = malloc(sizeof(struct
> quick_exit_handler));
You are making initialization at the declaration place, which is
not recommended by style.
> +
> + if (0 == h) {
Why 0 and not NULL ? Later, you use NULL. The {} are not needed.
> + return 1;
This shall be return (1);
> + }
> + h->cleanup = func;
> + pthread_mutex_lock(&atexit_mutex);
Note that libc code is careful to only call pthread mutex functions
if __isthreaded variable is set.
Also note that libc uses mangled names to allow the application interposition
of the functions. E.g. ANSI C code is allowed to have pthread_mutex_lock()
function defined.
> + h->next = handlers;
> + handlers = h;
> + pthread_mutex_unlock(&atexit_mutex);
> + return 0;
And this shall be return (0);
> +}
> +
> +void quick_exit(int status)
The function name shall start at the column 0.
> +{
> + /*
> + * XXX: The C++ spec requires us to call std::terminate if there is an
> + * exception here.
> + */
> + for (struct quick_exit_handler *h = handlers ; NULL != h ; h = h->next)
This fragment violates so many style requirements that I probably fail
to enumerate them all.
The h declaration shall go at the start of function, and not at the for
statement.
The opening '{' shall be placed on the line of 'for'. More, the {} bracing
is not needed there.
No space is needed before ';', three times.
> + {
> + h->cleanup();
> + }
> + _Exit(status);
> +}
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