S3 class for run-time type information of foreign C data types

S3 class for run-time type information of foreign C data types.

Usage

typeinfo(
  name,
  type = c("base", "pointer", "struct", "union"),
  size = NA,
  align = NA,
  basetype = NA,
  fields = NA,
  signature = NA
)

# S3 method for class 'typeinfo'
print(x, ...)

get_typeinfo(name, envir = parent.frame())

Arguments

name

character string specifying the type name.

type

character string specifying the type.

size

integer, size of type in bytes.

align

integer, alignment of type in bytes.

basetype

character string, base type of 'pointer' types.

fields

data frame with name, type, offset and optional array or bitfield layout information that specifies aggregate struct and union types.

signature

character string specifying the struct/union type signature.

x

S3 typeinfo object to print.

...

additional arguments to be passed to base::print() methods.

envir

the environment to look for type object.

Value

List object tagged as S3 class typeinfo with the following named entries

type

Type name.

size

Size in bytes.

align

Alignment in bytes.

fields

Data frame for field information with the following columns:

name	field name
type	type name
offset	byte offset (starts counted from 0)
array_len	fixed array length, or 1 for scalar fields
bit_offset	bitfield offset, or NA for ordinary fields
bit_width	bitfield width, or NA for ordinary fields
storage_offset	bitfield storage-unit byte offset
storage_size	bitfield storage-unit size in bytes

Details

Type information objects are created at run-time to describe the concrete layout of foreign C data types on the host machine. While type signatures give an abstract information on e.g. the field types and names of aggregate structure types, these objects store concrete memory size, alignment and layout information about C data types.

See also

cstruct() for details on the framework for handling foreign C data types.