[glibc] manual: Document unsupported cases for interposition

[glibc] manual: Document unsupported cases for interposition

[Siddhesh Poyarekar]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=d34ed66f96fa9316654d7adb2afcce4be1d1c4f5

commit d34ed66f96fa9316654d7adb2afcce4be1d1c4f5
Author: Siddhesh Poyarekar <siddhesh@sourceware.org>
Date:   Fri Jul 23 20:26:01 2021 +0530

    manual: Document unsupported cases for interposition
    
    These functions call the core allocator functions (realloc and malloc
    respectively) and are hence guaranteed to allocate memory using the
    correct functions when multiple allocators are interposed.  Having
    these functions interposed in one allocator and not another may result
    in confusion, hence discourage interposing them altogether.
    
    Reviewed-by: Florian Weimer <fweimer@redhat.com>

Diff:
---
 manual/memory.texi | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/manual/memory.texi b/manual/memory.texi
index 69c8894602..a51ed42516 100644
--- a/manual/memory.texi
+++ b/manual/memory.texi
@@ -1864,6 +1864,13 @@ when a replacement @code{malloc} is in use.  However, failure to replace
 these functions typically does not result in crashes or other incorrect
 application behavior, but may result in static linking failures.
 
+There are other functions (@code{reallocarray}, @code{strdup}, etc.) in
+@theglibc{} that are not listed above but return newly allocated memory to
+callers.  Replacement of these functions is not supported and may produce
+incorrect results.  @Theglibc{} implementations of these functions call
+the replacement allocator functions whenever available, so they will work
+correctly with @code{malloc} replacement.
+
 @node Obstacks
 @subsection Obstacks
 @cindex obstacks