setCheckSEXP(value)

The .Call and .External functions pass Rapi object pointers (with the C type SEXP) to a C function, which returns an SEXP value. The C function can call into the engine, passing SEXP arguments to Rapi entry functions.

If the C function has a mistake, it might pass the engine a garbage value as an SEXP argument, or it might return a garbage pointer. If the engine tries to follow this pointer, it can cause a segmentation fault and crash the process.

To avoid this possible outcome, TIBCO Enterprise Runtime for R optionally maintains a hash table containing all of the known SEXP pointers. TIBCO Enterprise Runtime for R uses this table to check each SEXP it is given, giving an error or a warning if a bad SEXP is found, rather than crashing. This behavior is optional because updating and checking this table significantly decreases the performance of the engine.

The setCheckSEXP function is used to enable or disable this table of SEXP values.

• If value is set to TRUE, the hash table is enabled.
• If value is set to FALSE, the hash table is disbled.
• If value is set to NA, the current state is returned.

Note

Enabling the SEXP checks is an expensive operation because the engine has to scan through all objects.

Currently, this table is enabled by default when TIBCO Enterprise Runtime for R starts. In a later release, this setting might be changed to be disabled by default.

Warning

If this table is disabled, it is possible that TIBCO Enterprise Runtime for R might crash if it calls external C code that produces garbage values.

## return whether SEXP values are checked
setCheckSEXP(NA)