Commit 1075139c authored by Pauli's avatar Pauli
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Add documentation for CRYPTO_memcmp. 



Reviewed-by: default avatarMatthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/9225)

(cherry picked from commit 0ccff7a7ea82a921f780a483fc91c6b90a1378d9)
parent a7581949

doc/man3/CRYPTO_memcmp.pod

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=pod



=head1 NAME



CRYPTO_memcmp - Constant time memory comparison



=head1 SYNOPSIS



 #include <openssl/crypto.h>



 int CRYPTO_memcmp(const void *a, const void *b, size_t len);



=head1 DESCRIPTION



The CRYPTO_memcmp function compares the B<len> bytes pointed to by B<a> and B<b>

for equality.

It takes an amount of time dependent on B<len>, but independent of the

contents of the memory regions pointed to by B<a> and B<b>.



=head1 RETURN VALUES



CRYPTO_memcmp() returns 0 if the memory regions are equal and non-zero

otherwise.



=head1 NOTES



Unlike memcmp(2), this function cannot be used to order the two memory regions

as the return value when they differ is undefined, other than being non-zero.



=head1 COPYRIGHT



Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.



Licensed under the Apache License 2.0 (the "License").  You may not use

this file except in compliance with the License.  You can obtain a copy

in the file LICENSE in the source distribution or at

L<https://www.openssl.org/source/license.html>.



=cut