IBM C and C++ Compilers returns the highest return code it receives from executing the various phases of compilation. These codes are:
| Code | Meaning |
| 0 | The compilation was completed, and no errors were detected. Any warnings have been written to stdout. Your executable file should run successfully. |
| 12 | Error detected; compilation may have been completed; successful execution impossible. |
| 16 | Severe error detected; compilation terminated abnormally; successful execution impossible. |
| 20 | Unrecoverable error detected;
compilation terminated abnormally and abruptly;
successful execution impossible. If the error code is greater than 20, contact your IBM service representative. |
For every compilation, the compiler generates a return code that indicates to the operating system the degree of success or failure it achieved.