It seems that OCI/Oracle installs signal handlers (*nix) and exception filters (Windows) per default to handle incidents of segmentation faults (*nix), access violations (Windows) etc. in order to log diagnostics. The documentation describes where incidents are reported and how to examine them using the Oracle utility adrci
.
Setting
DIAG_SIGHANDLER_ENABLED=FALSE
in the configuration file sqlnet.ora
disables the OCI signal handler / exception filter and re-enables standard operating system failure processing.