,I)Berkeley DB: DbLog::unlink[P

DbLog::unlink





#include <db_cxx.h>

static int3DbLog::unlink(const char *dir, int force, DbEnv *);





Description



UThe DbLog::unlink function destroys the log region identified by the directory@dir, removing all files used to implement the log region.H(The log files themselves and the directory dir are not removed.)

©If there are processes that have called DbLog::open without calling DbLog::closeS(i.e., there are processes currently using the log region), DbLog::unlink will failQwithout further action, unless the force flag is set, in which case DbLog::unlinkWwill attempt to remove the log region files regardless of any processes still using it.

FThe result of attempting to forcibly destroy the region when a process#has the region open is unspecified.GProcesses using a shared memory region maintain an open file descriptorfor it.2On UNIX systems, the region removal should succeedDand processes that have already joined the region should continue to!run in the region without change,Ohowever processes attempting to join the log region will either fail or attemptto create a new region.FOn other systems (e.g., Windows/NT), where the unlink(2) systemKcall will fail if any process has an open file descriptor for the file, theregion removal will fail.

HIn the case of catastrophic or system failure, database recovery must benperformed (see db_recover), or the DB_RECOVER and DB_RECOVER_FATALYflags to DbEnv::appinit must be specified.GAlternatively, if recovery is not required because no database state isOmaintained across failures, it is possible to clean up a log region by removingtall of the files in the directory specified to the DbLog::open function,:as no log region files are created in any other directory.ENote, however, that this has the potential to remove files created byBthe other Berkeley DB subsystems in the same database environment.

The DbLog::unlink>method either returns errno or throws an exception that:encapsulates an errno on failure, and 0 on success.



Errors

TIf a fatal error occurs in Berkeley DB, the DbLog::unlink method may fail and eitherIreturn DB_RUNRECOVERY or throw an exception encapsulating DB_RUNRECOVERY,Gat which point all subsequent database calls will also fail in the sameFway. Methods marked as returning errno will, by default, throwHan exception that encapsulates the error information. The default error\behavior can be changed, see DbException.

The DbLog::unlink&method may fail and throw an exceptionKfor any of the errors specified for the following Berkeley DB and C library functions: abort(3), close(3),>DbEnv::version, fcntl(3), fflush(3), fprintf(3),free(3), fstat(3), fsync(3), getenv(3), getpid(3), getuid(3), isdigit(3), lseek(3), malloc(3), memcpy(3), memset(3),mmap(3), munmap(3),open(3),pstat_getdynamic(3),read(3), shmat(3), shmctl(3), shmdt(3),sigfillset(3),sigprocmask(3),stat(3), strerror(3), strlen(3), sysconf(3), unlink(3), vfprintf(3), vsnprintf(3),and write(3).

In addition, the DbLog::unlink&method may fail and throw an exceptionor return errnofor the following conditions:

S

EBUSY
The shared memory region was in use and the force flag was not set.




Class

2DbLog



See Also

>DbLog::archive,:DbLog::close,>DbLog::compare,8DbLog::file,:DbLog::flush,6DbLog::get,8DbLog::open,6DbLog::put,FDbLog::db_register,8DbLog::stat, DbLog::unlinkandJDbLog::db_unregister.
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