kvm_geterr(3) [freebsd man page]

KVM_GETERR(3)						   BSD Library Functions Manual 					     KVM_GETERR(3)

NAME

     kvm_geterr -- get error message on kvm descriptor

LIBRARY

     Kernel Data Access Library (libkvm, -lkvm)

SYNOPSIS

     #include <kvm.h>

     char *
     kvm_geterr(kvm_t *kd);

DESCRIPTION

     This function returns a string describing the most recent error condition on the descriptor kd.  The results are undefined if the most recent
     kvm(3) library call did not produce an error.  The string returned is stored in memory owned by kvm(3) so the message should be copied out
     and saved elsewhere if necessary.

SEE ALSO

     kvm(3), kvm_close(3), kvm_getargv(3), kvm_getenvv(3), kvm_getprocs(3), kvm_nlist(3), kvm_open(3), kvm_openfiles(3), kvm_read(3), kvm_write(3)

BUGS

     This routine cannot be used to access error conditions due to a failed kvm_openfiles() call, since failure is indicated by returning a NULL
     descriptor.  Therefore, errors on open are output to the special error buffer passed to kvm_openfiles().  This option is not available to
     kvm_open().

BSD
								   June 4, 1993 							       BSD

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 /dev/mem while crash dumps can be examined via the core file generated by savecore(8).  The interface behaves identically
     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.

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

FILES

     /dev/mem  interface to physical memory

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_getkernelname(3), kvm_getloadavg(3), kvm_getlwps(3), kvm_getprocs(3),
     kvm_nlist(3), kvm_open(3), kvm_openfiles(3), kvm_read(3), kvm_write(3)

BSD
								September 14, 2011							       BSD