Chapter 11. Symbol Table

If an executable file contains a reference to a function defined in one of its associated shared objects, the symbol table section for that file shall contain an entry for that symbol. The st_shndx member of that symbol table entry contains SHN_UNDEF. This signals to the dynamic linker that the symbol definition for that function is not contained in the executable file itself. If that symbol has been allocated a procedure linkage table entry in the executable file, and the st_value member for that symbol table entry is non-zero, the value shall contain the virtual address of the first instruction of that procedure linkage table entry. Otherwise, the st_value member contains zero. This procedure linkage table entry address is used by the dynamic linker in resolving references to the address of the function.

Need to add something here about st_info and st_other ...