1*4724848cSchristos=pod 2*4724848cSchristos 3*4724848cSchristos=head1 NAME 4*4724848cSchristos 5*4724848cSchristosCRYPTO_memcmp - Constant time memory comparison 6*4724848cSchristos 7*4724848cSchristos=head1 SYNOPSIS 8*4724848cSchristos 9*4724848cSchristos #include <openssl/crypto.h> 10*4724848cSchristos 11*4724848cSchristos int CRYPTO_memcmp(const void *a, const void *b, size_t len); 12*4724848cSchristos 13*4724848cSchristos=head1 DESCRIPTION 14*4724848cSchristos 15*4724848cSchristosThe CRYPTO_memcmp function compares the B<len> bytes pointed to by B<a> and B<b> 16*4724848cSchristosfor equality. 17*4724848cSchristosIt takes an amount of time dependent on B<len>, but independent of the 18*4724848cSchristoscontents of the memory regions pointed to by B<a> and B<b>. 19*4724848cSchristos 20*4724848cSchristos=head1 RETURN VALUES 21*4724848cSchristos 22*4724848cSchristosCRYPTO_memcmp() returns 0 if the memory regions are equal and nonzero 23*4724848cSchristosotherwise. 24*4724848cSchristos 25*4724848cSchristos=head1 NOTES 26*4724848cSchristos 27*4724848cSchristosUnlike memcmp(2), this function cannot be used to order the two memory regions 28*4724848cSchristosas the return value when they differ is undefined, other than being nonzero. 29*4724848cSchristos 30*4724848cSchristos=head1 COPYRIGHT 31*4724848cSchristos 32*4724848cSchristosCopyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved. 33*4724848cSchristos 34*4724848cSchristosLicensed under the Apache License 2.0 (the "License"). You may not use 35*4724848cSchristosthis file except in compliance with the License. You can obtain a copy 36*4724848cSchristosin the file LICENSE in the source distribution or at 37*4724848cSchristosL<https://www.openssl.org/source/license.html>. 38*4724848cSchristos 39*4724848cSchristos=cut 40