From: Lasse Collin <lasse.collin@tukaani.org>
Date: Mon, 29 Sep 2025 15:37:19 +0000 (+0300)
Subject: liblzma: Document that lzma_allocator.free(opaque, NULL) is possible
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=61b114e92f53b7977aad69f8a7130fc25d8a80e5;p=thirdparty%2Fxz.git

liblzma: Document that lzma_allocator.free(opaque, NULL) is possible

It feels better to fix the docs than change the code because this
way newly-written applications will be forced to be compatible with
the lzma_allocator behavior of old liblzma versions. It can matter
if someone builds the application against an older liblzma version.

Fixes: https://github.com/tukaani-project/xz/issues/183
---

diff --git a/src/liblzma/api/lzma/base.h b/src/liblzma/api/lzma/base.h
index 0589cde2..00499381 100644
--- a/src/liblzma/api/lzma/base.h
+++ b/src/liblzma/api/lzma/base.h
@@ -450,7 +450,9 @@ typedef struct {
 	 * \param       opaque  lzma_allocator.opaque (see below)
 	 * \param       ptr     Pointer returned by lzma_allocator.alloc(),
 	 *                      or when it is set to NULL, a pointer returned
-	 *                      by the standard malloc().
+	 *                      by the standard malloc(). In addition, NULL
+	 *                      is a possible value. The function should do
+	 *                      nothing when ptr == NULL.
 	 */
 	void (LZMA_API_CALL *free)(void *opaque, void *ptr);