Berkeley DB

Tcl Error Handling

The Tcl interfaces to Berkeley DB generally return TCL_OK on success and throw a Tcl error on failure, using the appropriate Tcl interfaces to provide the user with an informative error message. There are some “expected” failures, however, for which no Tcl error will be thrown and for which Tcl commands will return TCL_OK. These failures include times when a searched-for key is not found, a requested key/data pair was previously deleted, or a key/data pair cannot be written because the key already exists.

These failures can be detected by searching the Berkeley DB error message that is returned. For example, use the following to detect that an attempt to put a record into the database failed because the key already existed: ...