A C program is naturally reentrant if it contains
no modifiable external data. In C, the following are considered modifiable
external data:
- Variables using the extern storage class
- Variables using the static storage class
- Writable strings
If your C program is naturally reentrant, you do not need to use
the RENT compiler option. After compiling and binding, install it
in one of the locations listed in Installing a reentrant load module.