Name
	n3619, alx-0027r1 - add [w]memzero(), [w]memzero_explicit()

Principles
	-  Codify existing practice to address evident deficiencies.
	-  Enable secure programming

Category
	Standardize common string APIs

Author
	Alejandro Colomar <alx@kernel.org>

History
	<https://www.alejandro-colomar.es/src/alx/alx/wg14/alx-0027.git/>

	r0 (2025-06-14):
	-  Initial draft.

	r1 (2025-06-26; n3619):
	-  s/Description/Rationale/

Rationale
	It is a common operation to zero an object.  This operation is
	significantly more common than memsetting any other value.
	Thus, it is useful and common to use an API that sets to zero,
	without accepting a parameter with the value to set.  It's easy
	to accidentally swap the order of the parameters to memset(3),
	resulting in bugs.

Design decisions
	It is interesting to return the input pointer.  This allows
	chaining calls: free(memzero_explicit(s, strlen(s))).

	bzero(3) already exists in POSIX systems (even though it was
	removed by POSIX).  However, it returns void, which is
	unfortunate.  For consistency with the rest of the ISO C string
	library, and for being able to return a pointer, let's use the
	name memzero(), which gives us some freedom.

Proposed wording
	Based on N3550.

    7.28.6  String handling <string.h> :: Miscellaneous functions
	## New section after 7.28.6.1 ("The memset function")

	+7.28.6.1+1  The <b>memzero</b> function
	+
	+Synopsis
	+1	#include <string.h>
	+	void *memzero(const void *p, size_t n);
	+
	+Description
	+2	The <b>memzero</b> function
	+	is equivalent to <b>memset</b>
	+	with its second argument set to 0.

	## New section after 7.28.6.2 ("The memset_explicit function")

	+7.28.6.2+1  The <b>memzero_explicit</b> function
	+
	+Synopsis
	+1	#include <string.h>
	+	void *memzero_explicit(const void *p, size_t n);
	+
	+Description
	+2	The <b>memzero_explicit</b> function
	+	is equivalent to <b>memset_explicit</b>
	+	with its second argument set to 0.

    7.33.4.7  General wide string utilities :: Miscellaneous functions
	## New sections after 7.33.4.7.3 ("The wmemset function")

	+7.33.4.7.3+1  The <b>wmemzero</b> function
	+
	+Synopsis
	+1	#include <wchar.h>
	+	wchar_t *wmemzero(const wchar_t *p, size_t n);
	+
	+Description
	+2	The <b>wmemzero</b> function
	+	is equivalent to <b>memzero</b>
	+	except that it handles wide characters.
	+
	+7.33.4.7.3+2  The <b>wmemzero_explicit</b> function
	+
	+Synopsis
	+1	#include <wchar.h>
	+	wchar_t *wmemzero_explicit(const wchar_t *p, size_t n);
	+
	+Description
	+2	The <b>wmemzero_explicit</b> function
	+	is equivalent to <b>memzero_explicit</b>
	+	except that it handles wide characters.

	## We should probably also add wmemset_explicit(), for
	## consistency.