freebsd man page for kvm

KVM(3)							   BSD Library Functions Manual 						    KVM(3)

NAME
     kvm -- kernel memory interface

LIBRARY
     Kernel Data Access Library (libkvm, -lkvm)

DESCRIPTION
     The kvm library provides a uniform interface for accessing kernel virtual memory images, including live systems and crash dumps.  Access to
     live systems is via sysctl(3) for some functions, and mem(4) and kmem(4) for other functions, while crash dumps can be examined via the core
     file generated by savecore(8).  The interface behaves similarly in both cases.  Memory can be read and written, kernel symbol addresses can
     be looked up efficiently, and information about user processes can be gathered.

     The kvm_open() function is first called to obtain a descriptor for all subsequent calls.

COMPATIBILITY
     The kvm interface was first introduced in SunOS.  A considerable number of programs have been developed that use this interface, making back-
     ward compatibility highly desirable.  In most respects, the Sun kvm interface is consistent and clean.  Accordingly, the generic portion of
     the interface (i.e., kvm_open(), kvm_close(), kvm_read(), kvm_write(), and kvm_nlist()) has been incorporated into the BSD interface.
     Indeed, many kvm applications (i.e., debuggers and statistical monitors) use only this subset of the interface.

     The process interface was not kept.  This is not a portability issue since any code that manipulates processes is inherently machine depen-
     dent.

     Finally, the Sun kvm error reporting semantics are poorly defined.  The library can be configured either to print errors to stderr automati-
     cally, or to print no error messages at all.  In the latter case, the nature of the error cannot be determined.  To overcome this, the BSD
     interface includes a routine, kvm_geterr(3), to return (not print out) the error message corresponding to the most recent error condition on
     the given descriptor.

SEE ALSO
     kvm_close(3), kvm_getargv(3), kvm_getenvv(3), kvm_geterr(3), kvm_getfiles(3), kvm_getloadavg(3), kvm_getprocs(3), kvm_getswapinfo(3),
     kvm_nlist(3), kvm_open(3), kvm_openfiles(3), kvm_read(3), kvm_write(3), sysctl(3), kmem(4), mem(4)

BSD
								  April 25, 2010							       BSD