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KVM(3)		       FreeBSD 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 mem(4) and kmem(4) while crash dumps can be	examined via
     the core file generated by	savecore(8).  The interface behaves identi-
     cally in both cases.  Memory can be read and written, kernel symbol
     addresses can be looked up	efficiently, and information about user	pro-
     cesses 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 backward
     compatibility highly desirable.  In most respects,	the Sun	kvm interface
     is	consistent and clean.  Accordingly, the	generic	portion	of the inter-
     face (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	automatically,
     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),
     kmem(4), mem(4)

FreeBSD	10.1		       January 29, 2004			  FreeBSD 10.1

NAME | LIBRARY | DESCRIPTION | COMPATIBILITY | SEE ALSO

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