Types of files
QNX Neutrino supports various types of files.
The ls -l command uses the character shown in parentheses below to identify the file type:
- Regular (-)
- A file that contains user data, such as C code, HTML, and data. For example, /home/fred/myprog.c.
- Directory (d)
- Conceptually, a directory is something that contains files and other
directories. For example, /home/fred.
A directory is implemented as a disk file that stores a list of the names of files and other directories. Each filename is associated with an inode (information node) that defines the file's existence.
- Symbolic link (l)
- An additional name for a file or directory.
- Named special (n)
- A shared memory region, such as, /dev/shmem/Pg101e0001.
- Character special files (c)
- Entries that represent a character device. For example, /dev/ser1 represents a serial port.
- FIFO special files (p)
- Persistent named pipes through which two programs communicate. For example, PipeA.
- Block special files (b)
- Entries that represent a block device, such as a disk. For example, /dev/hd0 represents the raw block data of your primary disk drive.
- Socket files (s)
- Entries that represent a communications socket, especially a UNIX-domain socket. For more information, see socket() and the UNIX protocol in the QNX Neutrino C Library Reference.
Some files are persistent across system reboots, such as most files in a disk filesystem. Other files may exist only as long as the program responsible for them is running. Examples of these include shared memory objects, objects in the /proc filesystem, and temporary files on disk that are still being accessed even though the links to the files (their filenames) have been removed.