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Selecting Bitcoin network parameters at startup

The code behind the network, with room to understand it.

Stable release v32.1bitcoin/bitcoin · f0de87f04062 ↗3,020 source files · 47.5 MB stored on the server440 file guides

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1// Copyright (c) 2009-2010 Satoshi Nakamoto
2// Copyright (c) 2009-present The Bitcoin Core developers
3// Distributed under the MIT software license, see the accompanying
4// file COPYING or http://www.opensource.org/licenses/mit-license.php.
5
6#ifndef BITCOIN_CHAINPARAMS_H
7#define BITCOIN_CHAINPARAMS_H
8
9#include <kernel/chainparams.h> // IWYU pragma: export
10
11#include <memory>
12
13class ArgsManager;
14
15/**
16 * Creates and returns a std::unique_ptr<CChainParams> of the chosen chain.
17 */
18std::unique_ptr<const CChainParams> CreateChainParams(const ArgsManager& args, ChainType chain);
19
20/**
21 * Return the currently selected parameters. This won't change after app
22 * startup, except for unit tests.
23 */
24const CChainParams &Params();
25
26/**
27 * Sets the params returned by Params() to those for the given chain type.
28 */
29void SelectParams(ChainType chain);
30
31#endif // BITCOIN_CHAINPARAMS_H
32

FILE GUIDE · KEY SECTIONS

Selecting Bitcoin network parameters at startup

This header exposes chain-parameter construction and the application’s selected parameter set without embedding network constants here.

Line 18 ↗

Construct an immutable parameter object

CreateChainParams receives parsed arguments and a ChainType and returns unique ownership of constant parameters. The actual network-specific fields live in the kernel parameter definitions. Constructing parameters does not synchronize a node or verify its local block files.

Line 29 ↗

Separate construction from global selection

SelectParams chooses what Params returns. The interface documents that the chosen parameters normally remain fixed after startup, with unit tests as an exception. Code reading Params therefore relies on startup configuration rather than choosing its own network for each call.

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