Satoshi Bitcoin client variable explanation in main.h (Bitcoin Pseudocode Client

[Xenland]

This is for research for the Bitcoin Pseudocode Client project where we attempt at making the Bitcoin client in multiple lanaguages with complete documentation and proccesses on everything in everylanguage, so Bitcoin speaks to Every developer, I'm doing this for free so every little bit helps (Link to project: https://github.com/Xenland/Bitcoin-Pseudocode-Client/tree/gh-pages)

My question to you is... Does anyone know what the following variables are for in main.h?
I just know what MAX_MONEY is the 21 million hard limit but I can't find the COIN variable(but i assume it is the value of 100000000 for converting to satoshi) in any of the bitcoin source files(how do devs usual search for variables globally through a project?)

I'm guessing MAX_BLOCK_SIZE is the amount of transactions in one block but in what units i wonder? (kilobyte limit?, tx limit?, etc)
What is max orphan transactions? why even have a max orphans? why not just toss'em?

static const unsigned int MAX_BLOCK_SIZE = 1000000;
static const unsigned int MAX_BLOCK_SIZE_GEN = MAX_BLOCK_SIZE/2;
static const unsigned int MAX_BLOCK_SIGOPS = MAX_BLOCK_SIZE/50;
static const unsigned int MAX_ORPHAN_TRANSACTIONS = MAX_BLOCK_SIZE/100;
static const unsigned int MAX_INV_SZ = 50000;
static const unsigned int MAX_BLOCKFILE_SIZE = 0x8000000; // 128 MiB
static const unsigned int BLOCKFILE_CHUNK_SIZE = 0x1000000; // 16 MiB
static const unsigned int UNDOFILE_CHUNK_SIZE = 0x100000; // 1 MiB
static const unsigned int MEMPOOL_HEIGHT = 0x7FFFFFFF;
static const int64 MIN_TX_FEE = 50000;
static const int64 MIN_RELAY_TX_FEE = 10000;
static const int64 MAX_MONEY = 21000000 * COIN;
inline bool MoneyRange(int64 nValue) { return (nValue >= 0 && nValue <= MAX_MONEY); }
static const int COINBASE_MATURITY = 100;
// Threshold for nLockTime: below this value it is interpreted as block number, otherwise as UNIX timestamp.
static const unsigned int LOCKTIME_THRESHOLD = 500000000; // Tue Nov  5 00:53:20 1985 UTC

Thank you everyone!

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[CIYAM]

Not sure how you missed this but:

Code:

[main.h]
...
static const int64 COIN = 100000000;
...
static const int64 MAX_MONEY = 21000000 * COIN;

to find such symbols (assuming they are in .h files) simply:

Code:

grep COIN *.h

[Pieter Wuille]

static const unsigned int MAX_BLOCK_SIZE = 1000000;

Maximum size of a block in bytes, as specified by network rules.

static const unsigned int MAX_BLOCK_SIZE_GEN = MAX_BLOCK_SIZE/2;

Maximum size of a block that will be generated.

static const unsigned int MAX_BLOCK_SIGOPS = MAX_BLOCK_SIZE/50;

Maximum number of signature checking operations in a block, as specified by network rules

static const unsigned int MAX_ORPHAN_TRANSACTIONS = MAX_BLOCK_SIZE/100;

Maximum number of orphan transactions kept in memory; old ones are deleted when this number is exceeded

static const unsigned int MAX_INV_SZ = 50000;

Maximum number of entries in an "inv" protocol message

static const unsigned int MAX_BLOCKFILE_SIZE = 0x8000000; // 128 MiB

Maximum size of a block file (new in 0.8 )

static const unsigned int BLOCKFILE_CHUNK_SIZE = 0x1000000; // 16 MiB

Size of preallocation chunks in block files (new in 0.8 )

static const unsigned int UNDOFILE_CHUNK_SIZE = 0x100000; // 1 MiB

Size of preallocation chunks in undo files (new in 0.8 )

static const unsigned int MEMPOOL_HEIGHT = 0x7FFFFFFF;

Special height in CCoins to mark origin is mempool (memory only) (new in 0.8 )

Fees below this (in satoshi) are considered zero fee for purposes of block/tx creation

static const int64 MIN_TX_FEE = 50000;

static const int64 MIN_RELAY_TX_FEE = 10000;

Fees below this (in satoshi) are considered zero fee for purposes of relaying

static const int64 MAX_MONEY = 21000000 * COIN;

Maximum amount (in satoshi) allowed anywhere. COIN is equal to 10^8

static const int COINBASE_MATURITY = 100;

Coinbase transactions cannot be spent before this number of confirms

[Xenland]

Not sure how you missed this but:

Code:

[main.h]
...
static const int64 COIN = 100000000;
...
static const int64 MAX_MONEY = 21000000 * COIN;

to find such symbols (assuming they are in .h files) simply:

Code:

grep COIN *.h

That literately does not exist on main.h so I'm not sure which source code you are referring to.
Infact the integer 100000000 isn't even found on main.h on the github page https://github.com/bitcoin/bitcoin/blob/master/src/main.h

[Pieter Wuille]

COIN is defined in util.h, apparently. I assume because it's necessary for formatting amounts.

[Pieter Wuille]

i've submitted a pull request with comments for all those constants.

[Xenland]

Great stuff thanks everyone for the help, That's one step closer to compiling all this information together.

[CIYAM]

That literately does not exist on main.h so I'm not sure which source code you are referring to.
Infact the integer 100000000 isn't even found on main.h on the github page https://github.com/bitcoin/bitcoin/blob/master/src/main.h

Oops - I was looking at the source code on my own computer (so not up to date).

Guess there has been some reorg work done on the headers.

[kjj]

i've submitted a pull request with comments for all those constants.

Just out of curiosity, has MAX_BLOCK_SIGOPS always been defined as a fraction of the block size?  From the P2SH debates, I remember the number 20,000 which is what you get when you perform the division, but I don't remember the division.  And as I recall, it was somewhat important, as a change to it could potentially cause a hardfork.  And I can't find any documentation on it other than the source code, so I was wondering...

[Pieter Wuille]

i've submitted a pull request with comments for all those constants.

Just out of curiosity, has MAX_BLOCK_SIGOPS always been defined as a fraction of the block size?  From the P2SH debates, I remember the number 20,000 which is what you get when you perform the division, but I don't remember the division.  And as I recall, it was somewhat important, as a change to it could potentially cause a hardfork.  And I can't find any documentation on it other than the source code, so I was wondering...

Does that matter? Any change to MAX_BLOCK_SIGOPS or MAX_BLOCK_SIZE has hardforking risks - making one dependent on the other does not change that.