9.4. 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.