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ckb-std

CKB scripts run in a bare-metal environment (without relying on an operating system), meaning they lack support for commonly used development features like memory management, multi-threading/multi-processing scheduling, and I/O operations.

To address these issues, developers typically use ckb-std.

In the following sections, we will explain the details of ckb-std, and developers can refer to them according to their needs.

Below is a summary of the chapters and their corresponding APIs:

Entry & Allocator​

This chapter covers the tasks that need to be completed before the entry function (similar to the main function) is called, such as registering the entry function and creating a memory allocator.

Includes:

  • entry! macro: Defines the contract entry point.
  • default_alloc! macro: Defines the global allocator for no-std Rust.

Syscalls​

VM syscall defines additional capabilities provided by the CKB VM beyond the RISC-V instruction set. This chapter explains the details of these interfaces in ckb-std, as well as some higher-level abstractions that align with Rust style (found in high_level).

Include:

  • syscalls: Defines low level CKB syscalls.
  • ckb_constants: Static constants used in syscalls
  • high_level: Defines high level syscall API.

Error​

This chapter introduces the possible error values that may be returned when functions in ckb-std fail.

Include:

  • error

Logger​

During script development, logging can be used to assist with debugging.

Include:

  • debug!: A println! like macro helps debugging
  • logger: Advanced logging system.

Utils​

This chapter introduces some utility functions.

Include:

  • type_id
  • since: Transaction input's since field.

Dynamic loading & Exec​

This chapter covers the usage of Dynamic Loading and Exec, along with more internal details.

  • exec syscalls: VM syscalls 2
  • env: The Arg parameter of the entry function. (only spawn or exec)
  • dynamic_loading

Spawn​

The spawn API series implements a relatively complex IPC mechanism. This chapter will explain it in detail.

Others​

  • native-simulatorUsed to simulate CKB transactions in a native environment, which will be discussed in the Debug chapter.
  • dummy_atomic: Some Rust code can be compiled into atomic instructions for the RISC-V target. However, these atomic instructions are not supported on ckb-vm. To address this issue, this module has been introduced.