Hi Stephen, On 1/7/22 17:46, Stephen Kitt wrote:
int isn't large enough to store pointers on all platforms, use intptr_t instead.
Well, since the pointer came from a previous 'int', there should be no problem. But since the C language (or even POSIX) is very permissive about what a conforming implementation can do with pointers, and it only guarantees conversions to/from [u]intptr_t, I'd take this patch for correctness. However...
I still don't like at all the fact that compilers require an explicit cast. Casts are dangerous. Period. I haven't seen a place where casts are good, except when you explicitly want to rely on undefined behavior (which I've found very useful in a few cases). It should be clear to the compiler that we're doing the right thing, since we declared the variable to be 'intptr_t', which is by itself very rare. Requiring a cast adds no clarity, while it does increase the chances of a bug.
I'd like to know your opinion. I think I'll remove the cast, even if compilers are going to give a warning for implicitly converting from pointer to integer (intptr_t). I'd say patch the compiler, not the code.
Thanks, Alex
Signed-off-by: Stephen Kitt <steve@xxxxxxx> --- man3/malloc_info.3 | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/man3/malloc_info.3 b/man3/malloc_info.3 index a5b8d34f9..3baa891fd 100644 --- a/man3/malloc_info.3 +++ b/man3/malloc_info.3 @@ -198,7 +198,7 @@ static int numThreads, numBlocks; static void * thread_func(void *arg) { - int tn = (int) arg; + intptr_t tn = (intptr_t) arg;/* The multiplier \(aq(2 + tn)\(aq ensures that each thread (includingthe main thread) allocates a different amount of memory. */ @@ -237,7 +237,7 @@ main(int argc, char *argv[])/* Create threads that allocate different amounts of memory. */ - for (int tn = 0; tn < numThreads; tn++) {+ for (intptr_t tn = 0; tn < numThreads; tn++) { errno = pthread_create(&thr[tn], NULL, thread_func, (void *) tn); if (errno != 0)
-- Alejandro Colomar Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ http://www.alejandro-colomar.es/
