struct DefaultInit

Constructor to create an explicit 'uninitialized' instance.

This constructor can be used to pass an uninitialized `data` value to a

table driven parser function that does not use `data`. The purpose of this

is that it allows the compiler to reallocate and re-purpose the register

that is currently holding its value for other data. This reduces register

allocations inside the highly optimized varint parsing functions.

Applications not using `data` use the `PROTOBUF_TC_PARAM_NO_DATA_DECL`

macro to declare the standard input arguments with no name for the `data`

argument. Callers then use the `PROTOBUF_TC_PARAM_NO_DATA_PASS` macro.

Example:

if (ptr == nullptr) {

PROTOBUF_MUSTTAIL return Error(PROTOBUF_TC_PARAM_NO_DATA_PASS);

}