The kvm_nlist function retrieves the symbol table entries indicated by the name list argument nl. This argument points to an array of nlist structures, terminated by an entry whose n_name field is NULL (see nlist(3)). Each symbol is looked up using the n_name field, and if found, the corresponding n_type and n_value fields are filled in. These fields are set to 0 if the symbol is not found.
The kldsym(2) system call is used to locate the symbol. This is a less than perfect emulation of the nlist values but has the advantage of being aware of kernel modules and is reasonably fast.
The kvm_nlist function returns the number of invalid entries found. If the kernel symbol table was unreadable, -1 is returned.
kldsym(2), kvm(3), kvm_close(3), kvm_getargv(3), kvm_getenvv(3), kvm_geterr(3), kvm_getprocs(3), kvm_open(3), kvm_openfiles(3), kvm_read(3), kvm_write(3)