setsockopt: Protocol not available [Solved]

Problem code:

if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) 

{ 

perror("setsockopt"); 

exit(EXIT_FAILURE); 

}

Solution:

if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt))) 

{ 

perror("setsockopt"); 

exit(EXIT_FAILURE); 

}

Ref.: https://stackoverflow.com/a/59807281/4064166

[How To] Fix "Waiting to Upload" in iCloud Drive

1. Check if you have enough free storage on iCloud

2. Go to Settings (iOS / iPadOS) or System Preferences (macOS) >> iCloud >> Sign Out

3. Wait for a minute or two after you have successfully logged out

4. Log in to iCloud again

5. Go to iCloud settings and >> iCloud Drive >> Options... >> select the checkbox for "Desktop & Documents Folder" >> Done

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[How To] Use Cryptopp in Xcode

Crypto++ Library is a free C++ class library of cryptographic schemes. Currently the library contains the following algorithms:

                   algorithm type  name

 authenticated encryption schemes  GCM, CCM, EAX, ChaCha20Poly1305 and
                                   XChaCha20Poly1305

        high speed stream ciphers  ChaCha (8/12/20), ChaCha (IETF), Panama, Salsa20,
                                   Sosemanuk, XSalsa20, XChaCha20

           AES and AES candidates  AES (Rijndael), RC6, MARS, Twofish, Serpent,
                                   CAST-256

                                   ARIA, Blowfish, Camellia, CHAM, HIGHT, IDEA,
                                   Kalyna (128/256/512), LEA, SEED, RC5, SHACAL-2,
              other block ciphers  SIMON (64/128), Skipjack, SPECK (64/128),
                                   Simeck, SM4, Threefish (256/512/1024),
                                   Triple-DES (DES-EDE2 and DES-EDE3), TEA, XTEA

  block cipher modes of operation  ECB, CBC, CBC ciphertext stealing (CTS),
                                   CFB, OFB, counter mode (CTR), XTS

     message authentication codes  BLAKE2s, BLAKE2b, CMAC, CBC-MAC, DMAC, GMAC, HMAC,
                                   Poly1305, Poly1305 (IETF), SipHash, Two-Track-MAC,
                                   VMAC

                                   BLAKE2s, BLAKE2b, Keccack (F1600), SHA-1,
                   hash functions  SHA-2 (224/256/384/512), SHA-3 (224/256/384/512),
                                   SHAKE (128/256), SipHash, SM3, Tiger,
                                   RIPEMD (128/160/256/320), WHIRLPOOL

                                   RSA, DSA, Deterministic DSA, ElGamal,
          public-key cryptography  Nyberg-Rueppel (NR), Rabin-Williams (RW), LUC,
                                   LUCELG, EC-based German Digital Signature (ECGDSA),
                                   DLIES (variants of DHAES), ESIGN

   padding schemes for public-key  PKCS#1 v2.0, OAEP, PSS, PSSR, IEEE P1363
                          systems  EMSA2 and EMSA5

                                   Diffie-Hellman (DH), Unified Diffie-Hellman (DH2),
            key agreement schemes  Menezes-Qu-Vanstone (MQV), Hashed MQV (HMQV),
                                   Fully Hashed MQV (FHMQV), LUCDIF, XTR-DH

      elliptic curve cryptography  ECDSA, Deterministic ECDSA, ed25519, ECNR, ECIES,
                                   ECDH, ECMQV, x25519

          insecure or obsolescent  MD2, MD4, MD5, Panama Hash, DES, ARC4, SEAL
algorithms retained for backwards  3.0, WAKE-OFB, DESX (DES-XEX3), RC2,
     compatibility and historical  SAFER, 3-WAY, GOST, SHARK, CAST-128, Square
                            value

[How To] check if Intel SGX is enabled

Steps to check if Intel SGX is enabled on your system:

1. Download test-sgx.c from https://github.com/ayeks/SGX-hardware

2. % gcc test-sgx.c -o test-sgx

3. % ./test-sgx

eax: 806ea ebx: 4100800 ecx: 7ffafbbf edx: bfebfbff

stepping 10

model 14

family 6

processor type 0

extended model 8

extended family 0

smx: 0

Extended feature bits (EAX=07H, ECX=0H)

eax: 0 ebx: 29c67af ecx: 0 edx: 9c002600

sgx available: 1

sgx launch control: 0

CPUID Leaf 12H, Sub-Leaf 0 of Intel SGX Capabilities (EAX=12H,ECX=0)

eax: 0 ebx: 0 ecx: 0 edx: 0

sgx 1 supported: 0

sgx 2 supported: 0

MaxEnclaveSize_Not64: 0

MaxEnclaveSize_64: 0

CPUID Leaf 12H, Sub-Leaf 1 of Intel SGX Capabilities (EAX=12H,ECX=1)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 2 of Intel SGX Capabilities (EAX=12H,ECX=2)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 3 of Intel SGX Capabilities (EAX=12H,ECX=3)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 4 of Intel SGX Capabilities (EAX=12H,ECX=4)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 5 of Intel SGX Capabilities (EAX=12H,ECX=5)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 6 of Intel SGX Capabilities (EAX=12H,ECX=6)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 7 of Intel SGX Capabilities (EAX=12H,ECX=7)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 8 of Intel SGX Capabilities (EAX=12H,ECX=8)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 9 of Intel SGX Capabilities (EAX=12H,ECX=9)

eax: 0 ebx: 0 ecx: 0 edx: 0

4. sgx available = 1 means that the system has a CPU that supports Intel SGX

5. From sgx1 supported = 0 and max enclave size64 = 0 we infer that Intel SGX is disabled from BIOS

iOS v/s Android - Comparing 'Apples' to 'Oranges'

	Apple iOS	Google Android
Released	July 29, 2007	September 23, 2008
Latest Version	14	11
Website	https://www.apple.com/ios/ios-14/	https://www.android.com/
OS Model	Proprietary	Open Source
Languages	40	100
Assistant	Siri	Google Assistant
Apps	1,000,000 on App Store	2,000,000 on Play Store
Operating System	Unix	Linux
Latest Phone	iPhone 12	Pixel 5
Phone Website	https://www.apple.com/iphone	https://store.google.com/product/pixel_5

Let's compare some of the default apps on both platforms...