Completion of error handling

[elfring]

Would you like to add more error handling for return values from functions like the following?

• fopen ⇒ smwrDumpNFA
• printf ⇒ dumpData

[mdb256]

This is in debug code for developers, not enabled in production builds.

Furthermore checking the return value of printf() does nothing except reduce the readability of the code.

[elfring]

I suggest to avoid ignorance of return values a bit more.
Would you like to detect every error situation as early as possible (also for software debug builds)?