[API reference](https://evolu.dev/docs/api-reference) › [@evolu/sqlite-wasm](https://evolu.dev/docs/api-reference/sqlite-wasm) › [c-api](https://evolu.dev/docs/api-reference/sqlite-wasm/c-api) › sqlite3\_io\_methods\_layout
```ts
const sqlite3_io_methods_layout: {
members: {
iVersion: {
offset: 0;
signature: "i";
};
xCheckReservedLock: {
offset: 36;
signature: "i(pp)";
};
xClose: {
offset: 4;
signature: "i(p)";
};
xDeviceCharacteristics: {
offset: 48;
signature: "i(p)";
};
xFetch: {
offset: 68;
signature: "i(pjip)";
};
xFileControl: {
offset: 40;
signature: "i(pip)";
};
xFileSize: {
offset: 24;
signature: "i(pp)";
};
xLock: {
offset: 28;
signature: "i(pi)";
};
xRead: {
offset: 8;
signature: "i(ppij)";
};
xSectorSize: {
offset: 44;
signature: "i(p)";
};
xShmBarrier: {
offset: 60;
signature: "v(p)";
};
xShmLock: {
offset: 56;
signature: "i(piii)";
};
xShmMap: {
offset: 52;
signature: "i(piiip)";
};
xShmUnmap: {
offset: 64;
signature: "i(pi)";
};
xSync: {
offset: 20;
signature: "i(pi)";
};
xTruncate: {
offset: 16;
signature: "i(pj)";
};
xUnfetch: {
offset: 72;
signature: "i(pjp)";
};
xUnlock: {
offset: 32;
signature: "i(pi)";
};
xWrite: {
offset: 12;
signature: "i(ppij)";
};
};
sizeof: 76;
};
```
Defined in: [packages/sqlite-wasm/src/Constants.ts:653](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L653)
The layout of `sqlite3_io_methods` in this wasm build.
## Type Declaration
| Name | Type | Default value | Defined in |
| ------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `members` | \{ `iVersion`: \{ `offset`: `0`; `signature`: `"i"`; \}; `xCheckReservedLock`: \{ `offset`: `36`; `signature`: `"i(pp)"`; \}; `xClose`: \{ `offset`: `4`; `signature`: `"i(p)"`; \}; `xDeviceCharacteristics`: \{ `offset`: `48`; `signature`: `"i(p)"`; \}; `xFetch`: \{ `offset`: `68`; `signature`: `"i(pjip)"`; \}; `xFileControl`: \{ `offset`: `40`; `signature`: `"i(pip)"`; \}; `xFileSize`: \{ `offset`: `24`; `signature`: `"i(pp)"`; \}; `xLock`: \{ `offset`: `28`; `signature`: `"i(pi)"`; \}; `xRead`: \{ `offset`: `8`; `signature`: `"i(ppij)"`; \}; `xSectorSize`: \{ `offset`: `44`; `signature`: `"i(p)"`; \}; `xShmBarrier`: \{ `offset`: `60`; `signature`: `"v(p)"`; \}; `xShmLock`: \{ `offset`: `56`; `signature`: `"i(piii)"`; \}; `xShmMap`: \{ `offset`: `52`; `signature`: `"i(piiip)"`; \}; `xShmUnmap`: \{ `offset`: `64`; `signature`: `"i(pi)"`; \}; `xSync`: \{ `offset`: `20`; `signature`: `"i(pi)"`; \}; `xTruncate`: \{ `offset`: `16`; `signature`: `"i(pj)"`; \}; `xUnfetch`: \{ `offset`: `72`; `signature`: `"i(pjp)"`; \}; `xUnlock`: \{ `offset`: `32`; `signature`: `"i(pi)"`; \}; `xWrite`: \{ `offset`: `12`; `signature`: `"i(ppij)"`; \}; \} | - | [packages/sqlite-wasm/src/Constants.ts:655](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L655) |
| `members.iVersion` | \{ `offset`: `0`; `signature`: `"i"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:656](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L656) |
| `members.iVersion.offset` | `0` | `0` | [packages/sqlite-wasm/src/Constants.ts:656](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L656) |
| `members.iVersion.signature` | `"i"` | `"i"` | [packages/sqlite-wasm/src/Constants.ts:656](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L656) |
| `members.xCheckReservedLock` | \{ `offset`: `36`; `signature`: `"i(pp)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:665](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L665) |
| `members.xCheckReservedLock.offset` | `36` | `36` | [packages/sqlite-wasm/src/Constants.ts:665](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L665) |
| `members.xCheckReservedLock.signature` | `"i(pp)"` | `"i(pp)"` | [packages/sqlite-wasm/src/Constants.ts:665](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L665) |
| `members.xClose` | \{ `offset`: `4`; `signature`: `"i(p)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:657](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L657) |
| `members.xClose.offset` | `4` | `4` | [packages/sqlite-wasm/src/Constants.ts:657](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L657) |
| `members.xClose.signature` | `"i(p)"` | `"i(p)"` | [packages/sqlite-wasm/src/Constants.ts:657](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L657) |
| `members.xDeviceCharacteristics` | \{ `offset`: `48`; `signature`: `"i(p)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:668](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L668) |
| `members.xDeviceCharacteristics.offset` | `48` | `48` | [packages/sqlite-wasm/src/Constants.ts:668](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L668) |
| `members.xDeviceCharacteristics.signature` | `"i(p)"` | `"i(p)"` | [packages/sqlite-wasm/src/Constants.ts:668](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L668) |
| `members.xFetch` | \{ `offset`: `68`; `signature`: `"i(pjip)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:673](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L673) |
| `members.xFetch.offset` | `68` | `68` | [packages/sqlite-wasm/src/Constants.ts:673](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L673) |
| `members.xFetch.signature` | `"i(pjip)"` | `"i(pjip)"` | [packages/sqlite-wasm/src/Constants.ts:673](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L673) |
| `members.xFileControl` | \{ `offset`: `40`; `signature`: `"i(pip)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:666](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L666) |
| `members.xFileControl.offset` | `40` | `40` | [packages/sqlite-wasm/src/Constants.ts:666](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L666) |
| `members.xFileControl.signature` | `"i(pip)"` | `"i(pip)"` | [packages/sqlite-wasm/src/Constants.ts:666](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L666) |
| `members.xFileSize` | \{ `offset`: `24`; `signature`: `"i(pp)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:662](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L662) |
| `members.xFileSize.offset` | `24` | `24` | [packages/sqlite-wasm/src/Constants.ts:662](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L662) |
| `members.xFileSize.signature` | `"i(pp)"` | `"i(pp)"` | [packages/sqlite-wasm/src/Constants.ts:662](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L662) |
| `members.xLock` | \{ `offset`: `28`; `signature`: `"i(pi)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:663](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L663) |
| `members.xLock.offset` | `28` | `28` | [packages/sqlite-wasm/src/Constants.ts:663](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L663) |
| `members.xLock.signature` | `"i(pi)"` | `"i(pi)"` | [packages/sqlite-wasm/src/Constants.ts:663](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L663) |
| `members.xRead` | \{ `offset`: `8`; `signature`: `"i(ppij)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:658](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L658) |
| `members.xRead.offset` | `8` | `8` | [packages/sqlite-wasm/src/Constants.ts:658](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L658) |
| `members.xRead.signature` | `"i(ppij)"` | `"i(ppij)"` | [packages/sqlite-wasm/src/Constants.ts:658](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L658) |
| `members.xSectorSize` | \{ `offset`: `44`; `signature`: `"i(p)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:667](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L667) |
| `members.xSectorSize.offset` | `44` | `44` | [packages/sqlite-wasm/src/Constants.ts:667](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L667) |
| `members.xSectorSize.signature` | `"i(p)"` | `"i(p)"` | [packages/sqlite-wasm/src/Constants.ts:667](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L667) |
| `members.xShmBarrier` | \{ `offset`: `60`; `signature`: `"v(p)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:671](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L671) |
| `members.xShmBarrier.offset` | `60` | `60` | [packages/sqlite-wasm/src/Constants.ts:671](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L671) |
| `members.xShmBarrier.signature` | `"v(p)"` | `"v(p)"` | [packages/sqlite-wasm/src/Constants.ts:671](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L671) |
| `members.xShmLock` | \{ `offset`: `56`; `signature`: `"i(piii)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:670](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L670) |
| `members.xShmLock.offset` | `56` | `56` | [packages/sqlite-wasm/src/Constants.ts:670](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L670) |
| `members.xShmLock.signature` | `"i(piii)"` | `"i(piii)"` | [packages/sqlite-wasm/src/Constants.ts:670](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L670) |
| `members.xShmMap` | \{ `offset`: `52`; `signature`: `"i(piiip)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:669](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L669) |
| `members.xShmMap.offset` | `52` | `52` | [packages/sqlite-wasm/src/Constants.ts:669](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L669) |
| `members.xShmMap.signature` | `"i(piiip)"` | `"i(piiip)"` | [packages/sqlite-wasm/src/Constants.ts:669](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L669) |
| `members.xShmUnmap` | \{ `offset`: `64`; `signature`: `"i(pi)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:672](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L672) |
| `members.xShmUnmap.offset` | `64` | `64` | [packages/sqlite-wasm/src/Constants.ts:672](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L672) |
| `members.xShmUnmap.signature` | `"i(pi)"` | `"i(pi)"` | [packages/sqlite-wasm/src/Constants.ts:672](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L672) |
| `members.xSync` | \{ `offset`: `20`; `signature`: `"i(pi)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:661](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L661) |
| `members.xSync.offset` | `20` | `20` | [packages/sqlite-wasm/src/Constants.ts:661](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L661) |
| `members.xSync.signature` | `"i(pi)"` | `"i(pi)"` | [packages/sqlite-wasm/src/Constants.ts:661](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L661) |
| `members.xTruncate` | \{ `offset`: `16`; `signature`: `"i(pj)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:660](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L660) |
| `members.xTruncate.offset` | `16` | `16` | [packages/sqlite-wasm/src/Constants.ts:660](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L660) |
| `members.xTruncate.signature` | `"i(pj)"` | `"i(pj)"` | [packages/sqlite-wasm/src/Constants.ts:660](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L660) |
| `members.xUnfetch` | \{ `offset`: `72`; `signature`: `"i(pjp)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:674](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L674) |
| `members.xUnfetch.offset` | `72` | `72` | [packages/sqlite-wasm/src/Constants.ts:674](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L674) |
| `members.xUnfetch.signature` | `"i(pjp)"` | `"i(pjp)"` | [packages/sqlite-wasm/src/Constants.ts:674](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L674) |
| `members.xUnlock` | \{ `offset`: `32`; `signature`: `"i(pi)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:664](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L664) |
| `members.xUnlock.offset` | `32` | `32` | [packages/sqlite-wasm/src/Constants.ts:664](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L664) |
| `members.xUnlock.signature` | `"i(pi)"` | `"i(pi)"` | [packages/sqlite-wasm/src/Constants.ts:664](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L664) |
| `members.xWrite` | \{ `offset`: `12`; `signature`: `"i(ppij)"`; \} | - | [packages/sqlite-wasm/src/Constants.ts:659](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L659) |
| `members.xWrite.offset` | `12` | `12` | [packages/sqlite-wasm/src/Constants.ts:659](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L659) |
| `members.xWrite.signature` | `"i(ppij)"` | `"i(ppij)"` | [packages/sqlite-wasm/src/Constants.ts:659](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L659) |
| `sizeof` | `76` | `76` | [packages/sqlite-wasm/src/Constants.ts:654](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/sqlite-wasm/src/Constants.ts#L654) |