2.3. Error Numbers
The <errno.h> header file defines the following additional error numbers:
2.4. Signal Concepts
If a subsequent occurrence of a pending signal is generated, the signal is delivered or accepted more than once if a handler
has been set for the signal with SA_SIGINFO set.
2.5. Standard I/O Streams
When a file is opened with append mode, the file position indicator is initially positioned at the beginning of the file.