1=pod 2 3=head1 NAME 4 5CRYPTO_memcmp - Constant time memory comparison 6 7=head1 SYNOPSIS 8 9 #include <openssl/crypto.h> 10 11 int CRYPTO_memcmp(const void *a, const void *b, size_t len); 12 13=head1 DESCRIPTION 14 15The CRYPTO_memcmp function compares the B<len> bytes pointed to by B<a> and B<b> 16for equality. 17It takes an amount of time dependent on B<len>, but independent of the 18contents of the memory regions pointed to by B<a> and B<b>. 19 20=head1 RETURN VALUES 21 22CRYPTO_memcmp() returns 0 if the memory regions are equal and nonzero 23otherwise. 24 25=head1 NOTES 26 27Unlike memcmp(2), this function cannot be used to order the two memory regions 28as the return value when they differ is undefined, other than being nonzero. 29 30=head1 COPYRIGHT 31 32Copyright 2019 The OpenSSL Project Authors. All Rights Reserved. 33 34Licensed under the Apache License 2.0 (the "License"). You may not use 35this file except in compliance with the License. You can obtain a copy 36in the file LICENSE in the source distribution or at 37L<https://www.openssl.org/source/license.html>. 38 39=cut 40
