[PATCH 1/3] getline.3: !*lineptr is sufficient

* [PATCH 1/3] getline.3: !*lineptr is sufficient
@ 2021-06-12  8:27 Alejandro Colomar
  2021-06-12  8:27 ` [PATCH 2/3] ferror.3: tfix Alejandro Colomar
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Alejandro Colomar @ 2021-06-12  8:27 UTC (permalink / raw)
  To: mtk.manpages; +Cc: наб, linux-man, Alejandro Colomar

From: наб <nabijaczleweli@nabijaczleweli.xyz>

No implementation or spec requires *n to be 0 to allocate a new buffer:
  * musl checks for !*lineptr
    (and sets *n=0 for later allocations)
  * glibc checks for !*lineptr || !*n
    (but only because it allocates early)
  * NetBSD checks for !*lineptr
    (and sets *n=0 for later allocations)
    (but specifies *n => mlen(*lineptr) >= *n as a precondition,
     to which this appears to be an exception)
  * FreeBSD checks for !*lineptr and sets *n=0
    (and specifies !*lineptr as sufficient)
  * Lastly, POSIX.1-2017 specifies:
    > If *n is non-zero, the application shall ensure that *lineptr
    > either points to an object of size at least *n bytes,
    > or is a null pointer.

The new wording matches POSIX, even if it arrives at the point slightly
differently

Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
---
 man3/getline.3 | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/man3/getline.3 b/man3/getline.3
index a32d7e770..6641ecc35 100644
--- a/man3/getline.3
+++ b/man3/getline.3
@@ -59,9 +59,7 @@ one was found.
 .PP
 If
 .I "*lineptr"
-is set to NULL and
-.I *n
-is set 0 before the call, then
+is set to NULL before the call, then
 .BR getline ()
 will allocate a buffer for storing the line.
 This buffer should be freed by the user program
-- 
2.32.0


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