Not under development, kind of deprecated. I decided to split this wallet into three parts due to seperation of concerns.

IOTA C library: The library contains the basic operation to build an iota transaction bundle. POSIX, C99, thread-safe, no malloc. To make sure that it runs on any device in any operation system.

Wallet header files: Defines the universal header files which needs to get implemented. Higher level fund managment included.

Wallet implementation: An operation system, database etc. dependend implementation of an iota wallet.

The goal is that every application which includes the wallet header can run on any operation system and any implementation.

IOTA C library:

https://github.com/embedded-iota/iota-c-library

RIOS OS (IOTA C library):

https://github.com/Citrullin/RIOT/tree/master/pkg/iota-library

https://github.com/Citrullin/RIOT/tree/master/examples/iota_transaction_pthread

A big thanks to the people of the IOTA implementation of the Ledger Nano S. They create an amazing low footprint C light wallet implementation for the Nano S. We use this as base for the generic embedded C light wallet implementation.

Due to confusion of several people, a short explanation about the conversions. The API for the conversion is available in conversion.c and conversion.h.

In this context the following words have the following meaning:

Chars: Means the char representation of an Tryte. (ASCII character) A - Z and 9. (base-27 encoded ternary number) Bytes: Means a byte representation of trytes, optimized for low storage and memory usage.
Trits: Means a int8_t array representation of trits.
Trytes: Means a int8_t array representation of trytes.

One transaction = 2673 trytes = ((2673/81) * 48) Bytes = 2673*3 Trits = 2673 chars

 unsigned char address[81];
 char seedChars[] = "INSERT_SEED_HERE";
 unsigned char seedBytes[48];
 chars_to_bytes(seedChars, seedBytes, 81);
 get_public_addr(seedBytes, 0, 2, address);

 char charAddress[81];
 bytes_to_chars(address, charAddress, 48);

char *seed = "YOURSEEDSTRING"; // 81 ternary characters
char address_one[82] = {0};
char address_two[82] = {0};
char *tag = "ANTAG"; //27 ternary characters

//Define the output array, where the coins must go to.
TX_OUTPUT output_txs[] = 
    {{.address = "ANADDRESS", .value = 10000, .message = "", .tag = ""}}; //ANADDRESS => 81 ternary characters


//Define the input array. Where the coins come from
TX_INPUT input_txs[] = {{.key_index = 4, .balance = 10000}};

//Define the transaction chars array. The char trytes will saved in this array. (base-27 encoded)
char transaction_chars[10][2673];
//Get all raw transaction trytes. Will saved in transaction_chars
prepare_transfers(seed, 2, output_txs, 1, input_txs, 1, transaction_chars);