Some common primitive system data types

Some common primitive system data types

Type	Description
caddr_t	core address
clock_t	counter of clock ticks (process time)
comp_t	compressed clock ticks
dev_t	device numbers (major and minor)
fd_set	file descriptor sets
fpos_t	file position
gid_t	numeric group IDs
ino_t	i-node numbers
mode_t	file type, file creation mode
nlink_t	link counts for directory entries
off_t	file sizes and offsets (signed) (lseek)
pid_t	process IDs and process group IDs (signed)
ptrdiff_t	result of subtracting two pointers (signed)
rlim_t	resource limits
sig_atomic_t	data type that can be accessed atomically
sigset_t	signal set
size_t	sizes of objects (such as strings) (unsigned)
ssize_t	functions that return a count of bytes (signed) (read, write)
time_t	counter of seconds of calendar time
uid_t	numeric user IDs
wchar_t	can represent all distinct character codes