NLIST(3) Library Functions Manual NLIST(3)
nlist - get entries from name list
struct nlist nl[ ];
Nlist examines the name list in the given executable output file and
selectively extracts a list of values. The name list consists of an
array of structures containing names, types and values. The list is
terminated with a null name. Each name is looked up in the name list
of the file. If the name is found, the type and value of the name are
inserted in the next two fields. If the name is not found, both
entries are set to 0. See a.out(5) for the structure declaration.
This subroutine is useful for examining the system name list kept in
the file /unix. In this way programs can obtain system addresses that
are up to date.
All type entries are set to 0 if the file cannot be found or if it is
not a valid namelist.