dysymtab_command

This is the second set of the symbolic information which is used to support the data structures for the dynamically link editor.

The original set of symbolic information in the symtab_command which contains the symbol and string tables must also be present when this load command is present. When this load command is present the symbol table is organized into three groups of symbols: local symbols (static and debugging symbols) - grouped by module defined external symbols - grouped by module (sorted by name if not lib) undefined external symbols (sorted by name if MH_BINDATLOAD is not set, and in order the were seen by the static linker if MH_BINDATLOAD is set) In this load command there are offsets and counts to each of the three groups of symbols.

This load command contains a the offsets and sizes of the following new symbolic information tables: table of contents module table reference symbol table indirect symbol table The first three tables above (the table of contents, module table and reference symbol table) are only present if the file is a dynamically linked shared library. For executable and object modules, which are files containing only one module, the information that would be in these three tables is determined as follows: table of contents - the defined external symbols are sorted by name module table - the file contains only one module so everything in the file is part of the module. reference symbol table - is the defined and undefined external symbols

For dynamically linked shared library files this load command also contains offsets and sizes to the pool of relocation entries for all sections separated into two groups: external relocation entries local relocation entries For executable and object modules the relocation entries continue to hang off the section structures.