Hi!

On Tue, Aug 24, 2021 at 11:21:15AM +0200, Michael Kerrisk (man-pages) wrote:

On Mon, 23 Aug 2021 at 23:01, наб [off-list ref] wrote:

quoted

---
 man3/strdup.3 | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/man3/strdup.3 b/man3/strdup.3
index 1e1ac34de..963de7d48 100644
--- a/man3/strdup.3
+++ b/man3/strdup.3

@@ -99,9 +99,6 @@ and
 are similar, but use
 .BR alloca (3)
 to allocate the buffer.
-They are available only when using the GNU
-GCC suite, and suffer from the same limitations described in
-.BR alloca (3).

Dropping mention of GCC seems reasonable, but why drop the piece about
"same limitations..."?

That paragraph now reads
  strdupa() and strndupa() are similar, but use alloca(3) to allocate the buffer.

I think this is short and unflowery enough that nothing more is needed
(or, indeed, anything more would be detrimental) ‒ and clearly points to
"see alloca(3) for the limitations of that allocator".

Plus, it's not like malloc(3) doesn't have its problems, too,
but I don't see those being touted in the first paragraph;
reducing these to the bare minimum,
  strdup() copies into malloc(3) and you can free it with free(3),
  strndup() likewise, but up to n, and
  str[n]dupa() use alloca(3) instead ‒ be wary of what alloca(3) does!
doesn't really make sense ‒ it's obvious that, ex definitione,
alloca(3) suffers from alloca(3) problems and input limits,
just like malloc(3) from the malloc(3) suite's.

quoted

Signed-off-by: Ahelenia Ziemiańska <redacted>

This patch could do with a short commit message I think. See below.

How about something like this for the message?
  str[n]dupa() are available on every modern platform, incl. Clang,
  ICC, &c.; by shortening the third paragraph, it now points squarely
  to alloca(3), which is scary enough, so drop the extraneous warning

Best,
наб