The purpose of this library is to make the verification functionality that is critical to Bitcoin's consensus available to other applications, e.g. to language bindings.
The interface is defined in the C header bitcoinconsensus.h located in src/script/bitcoinconsensus.h.
bitcoinconsensus_version returns an unsigned int with the API version (currently 1).
bitcoinconsensus_verify_script returns an int with the status of the verification. It will be 1 if the input script correctly spends the previous output scriptPubKey.
const unsigned char *scriptPubKey - The previous output script that encumbers spending.unsigned int scriptPubKeyLen - The number of bytes for the scriptPubKey.const unsigned char *txTo - The transaction with the input that is spending the previous output.unsigned int txToLen - The number of bytes for the txTo.unsigned int nIn - The index of the input in txTo that spends the scriptPubKey.unsigned int flags - The script validation flags (see below).bitcoinconsensus_error* err - Will have the error/success code for the operation (see below).bitcoinconsensus_SCRIPT_FLAGS_VERIFY_NONEbitcoinconsensus_SCRIPT_FLAGS_VERIFY_P2SH - Evaluate P2SH (BIP16) subscriptsbitcoinconsensus_SCRIPT_FLAGS_VERIFY_DERSIG - Enforce strict DER (BIP66) compliancebitcoinconsensus_SCRIPT_FLAGS_VERIFY_NULLDUMMY - Enforce NULLDUMMY (BIP147)bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKLOCKTIMEVERIFY - Enable CHECKLOCKTIMEVERIFY (BIP65)bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKSEQUENCEVERIFY - Enable CHECKSEQUENCEVERIFY (BIP112)bitcoinconsensus_SCRIPT_FLAGS_VERIFY_WITNESS - Enable WITNESS (BIP141)bitcoinconsensus_ERR_OK - No errors with input parameters (see the return value of bitcoinconsensus_verify_script for the verification status)bitcoinconsensus_ERR_TX_INDEX - An invalid index for txTobitcoinconsensus_ERR_TX_SIZE_MISMATCH - txToLen did not match with the size of txTobitcoinconsensus_ERR_DESERIALIZE - An error deserializing txTobitcoinconsensus_ERR_AMOUNT_REQUIRED - Input amount is required if WITNESS is usedbitcoinconsensus_ERR_INVALID_FLAGS - Script verification flags are invalid (i.e. not part of the libconsensus interface)