int DbLockTab::vec(u_int32_t locker, u_int32_t flags, DB_LOCKREQ list, int nlist, DB_LOCKREQ **elistp);
The DbLockTab::vec method atomically obtains and releases one or more locks from the lock table. The DbLockTab::vec method is intended to support acquisition or trading of multiple locks under one lock table semaphore, as is needed for lock coupling or in multigranularity locking for lock escalation.
The locker argument specified to DbLockTab::vec is an unsigned 32-bit integer quantity. It represents the entity requesting or releasing the lock.
The flags value must be set to 0 or the following value:
The list array provided to DbLockTab::vec is typedef'd as DB_LOCKREQ. A DB_LOCKREQ structure has at least the following fields, which must be initialized before calling DbLockTab::vec:
The nlist argument specifies the number of elements in the list array.
If any of the requested locks cannot be acquired, or any of the locks to be released cannot be released, the operations before the failing operation are guaranteed to have completed successfully, and DbLockTab::vec returns a non-zero value. In addition, if elistp is not NULL, it is set to point to the DB_LOCKREQ entry that was being processed when the error occurred.
In the case of an error, DbLockTab::vec may return one of the following values:
Otherwise, the DbLockTab::vec method either returns errno or throws an exception that encapsulates an errno on failure, and 0 on success.
The DbLockTab::vec method may fail and throw an exception for any of the errors specified for the following Berkeley DB and C library functions: abort(3), fcntl(3), fflush(3), fprintf(3), fsync(3), getpid(3), isprint(3), DbLockTab::detect, lseek(3), memcpy(3), memset(3), mmap(3), munmap(3), printf(3), pstat_getdynamic(3), shmat(3), shmdt(3), strerror(3), sysconf(3), vfprintf(3), vsnprintf(3), and write(3).
In addition, the DbLockTab::vec method may fail and throw an exception or return errno for the following conditions: