V9009

Code

V9009

Message

Temporary buffer pool exhausted

A string operation asked the VM for a temporary buffer and the pool had no free slot, so the VM halted rather than overwrite a value still in use.

String operations such as CONCAT, LEFT, MID and INSERT write their result into a temporary buffer rather than straight into a variable. Those buffers come from a pool the VM allocates once, before the program starts, because the runtime allocates no memory while a program is running. The compiler sizes the pool from the program: it works out the most buffers that can be in use at the same moment along any path of calls, and records that number in the compiled file.

A buffer is returned to the pool as soon as its value is copied into a variable, so repeating a string operation does not need more buffers than running it once. A loop that builds a string needs the same pool as the same statement outside a loop.

Cause

In the current compiler this indicates a defect: the pool was sized smaller than the program turned out to need.

Report this as a bug at https://github.com/ironplc/ironplc/issues with the .iplc file and the source program that produced it.

Think IronPLC is wrong about this?

If you believe this diagnostic is incorrect, open an issue on GitHub with a small sample that demonstrates the problem.