iii.3.4-arglist.md

III.3.4 arglist – get argument list

Format	Assembly Format	Description
FE 00	arglist	Return argument list handle for the current method.

Stack Transition:

… → …, argListHandle

Description:

The arglist instruction returns an opaque handle (having type System.RuntimeArgumentHandle) representing the argument list of the current method. This handle is valid only during the lifetime of the current method. The handle can, however, be passed to other methods as long as the current method is on the thread of control. The arglist instruction can only be executed within a method that takes a variable number of arguments.

[Rationale: This instruction is needed to implement the C va_* macros used to implement procedures like printf. It is intended for use with the class library implementation of System.ArgIterator. end rationale]

Exceptions:

None.

Correctness:

It is incorrect CIL generation to emit this instruction except in the body of a method whose signature indicates it accepts a variable number of arguments.

Verifiability:

Its use is verifiable within the body of a method whose signature indicates it accepts a variable number of arguments, but verification requires that the result be an instance of the System.RuntimeArgumentHandle class.