Payloads and Structs

The public C ABI uses typed C structs for backend configuration, operation requests, continuation input, errors, interrupts, provider status rows, and typed result views. Include the installed header and treat it as the binding contract:

#include <galanthus/c_api/gln_capi.h>

Struct Conventions

Every public fixed-size input struct that has a struct_size field has a matching gln_default_* helper. Always call the helper and then fill the fields the operation needs. Batch submissions are constructed through their request builder: call gln_create_*_request_builder, populate the shared header with gln_default_*_request_header plus caller fills and apply it through gln_set_*_request_header, size the builder with gln_set_*_request_item_capacity, and append each row by initializing it with the matching gln_default_*_item helper, filling the per-item fields, and calling gln_add_*_request_item (or gln_add_direct_debit_batch_request_amended_item for amended SEPA direct debits). Submit the builder with gln_submit_batch_transfer or gln_submit_direct_debit_batch, then release it with the matching gln_destroy_*_request_builder and free the returned envelope with gln_destroy_backend_result.

gln_submit_transfer_request_t request = {0};
gln_default_submit_transfer_request(&request);
request.source_iban          = "DE02120300000000202051";
request.source_bic           = "BYLADEM1001";
request.source_name          = "Example GmbH";
request.recipient_iban       = "DE89370400440532013000";
request.recipient_bic        = "COBADEFFXXX";
request.recipient_name       = "Supplier GmbH";
request.amount               = "125.40";
request.purpose              = "Invoice 2026-05";
request.end_to_end_reference_or_null = "INV-2026-05";

Payment request semantics follow the relevant EPC SEPA scheme material for credit transfers and direct debits.

Backend Config Structs

FinTS Config

EBICS Config

The TLS public-key pin accepts the same sha256//... form used by libcurl's CURLOPT_PINNEDPUBLICKEY option.

Revolut Config

Wise Config

Operation Request Structs

Read Requests

gln_list_balances_request_t:

gln_list_transactions_request_t:

gln_list_holdings_request_t:

Payment Requests

gln_submit_transfer_request_t is used for normal transfers.

gln_submit_instant_transfer_request_t is used for instant transfers.

gln_submit_batch_transfer takes a gln_batch_transfer_request_builder_t. Set shared source fields through gln_batch_transfer_request_header_t, then add each gln_batch_transfer_item_t row to the builder.

Each gln_batch_transfer_item_t contains recipient IBAN/BIC/name, amount, currency, purpose, and optional end-to-end reference.

Direct Debit Requests

gln_submit_direct_debit_request_t submits one SEPA direct debit.

gln_submit_direct_debit_batch takes a gln_direct_debit_batch_request_builder_t. Creditor identity, collection date, and local instrument live on the batch header; debtor identity, amount, mandate, and sequence data live on each item. Add ordinary rows with gln_add_direct_debit_batch_request_item and amended rows with gln_add_direct_debit_batch_request_amended_item.

Standing Order and TAN Requests

gln_add_standing_order_request_t, gln_modify_standing_order_request_t, and gln_delete_standing_order_request_t share the standing-order payment fields. Modify and delete also require order_reference.

gln_set_tan_mode_request_t has one required field: security_function, copied from a row returned by gln_retrieve_tan_modes.

Continuation Input

Resume uses gln_continuation_input_t.

See Also

• Backend results
• Accounts, balances, and transactions
• Transfers
• Direct debits
• Standing orders