p21read refers to one of many executables built from STEPcode. Each p21read executable is specific to one EXPRESS schema and has a suffix indicating the schema. For example,

p21read_sdai_IFC4 p21read_sdai_ISO15926 p21read_sdai_ap203 p21read_sdai_ap242

p21read is useful for testing STEPcode. When invoked, it reads a Part 21 file into memory, creating an object to represent each instance. It then uses those objects methods to writes the instances to a new file. Warnings indicate potential problems, while errors indicate definite problems. Errors could be from one of three sources:

  • STEPcode itself
  • the Part 21 file
  • the EXPRESS schema


P21read can be found in the repo at src/test/p21read/p21read.cc