xref: /netbsd-src/share/man/man3/types.3 (revision 7b7e9ceaacde6b27a7eab3b83841c0b2d148b393)
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57.\"     @(#)types.5	8.1 (Berkeley) 6/5/93
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59.Dd April 10, 2011
60.Dt TYPES 3
61.Os
62.Sh NAME
63.Nm types
64.Nd standard system data types
65.Sh SYNOPSIS
66.In sys/types.h
67.Sh DESCRIPTION
68The
69.In sys/types.h
70header contains the common data types used in the system.
71Although these are meant to be used within the kernel,
72most of the system data types are accessible also to user code.
73A companion header
74.In sys/param.h ,
75typically used in the kernel,
76includes
77.In sys/types.h
78and provides additional types as well as other facilities (see
79.Xr param 3 ) .
80.Ss Standard Types
81The following standards-compliant system data types are defined:
82.Bl -column -offset indent \
83"suseconds_t " "process and process group IDs " "clock_settime(3) "
84.It Sy Type Ta Sy Typical use Ta Sy Example
85.It Va blkcnt_t Ta file block counts Ta Xr stat 2
86.It Va blksize_t Ta block sizes Ta Xr stat 2
87.It Va clock_t Ta system clock ticks Ta Xr clock 3
88.It Va clockid_t Ta clock IDs Ta Xr clock_settime 2
89.It Va dev_t Ta device IDs Ta Xr devname 3
90.It Va fsblkcnt_t Ta file system block counts Ta -
91.It Va fsfilcnt_t Ta file system file counts Ta -
92.It Va gid_t Ta group IDs Ta Xr getgid 2
93.It Va id_t Ta general identifier Ta Xr pset 3
94.It Va ino_t Ta file serial numbers Ta Xr fs 5
95.It Va key_t Ta interprocess communication Ta Xr ftok 3
96.It Va mode_t Ta file attributes Ta Xr stat 2
97.It Va nlink_t Ta link counts Ta Xr stat 2
98.It Va off_t Ta file sizes Ta Xr fseek 3
99.It Va pid_t Ta process and process group IDs Ta Xr getpid 2
100.It Va size_t Ta size of objects Ta Xr stddef 3
101.It Va ssize_t Ta count of bytes Ta Xr write 2
102.It Va suseconds_t Ta microseconds Ta Xr gettimeofday 2
103.It Va time_t Ta time in seconds Ta Xr time 3
104.It Va timer_t Ta timer IDs Ta Xr timer_create 2
105.\"
106.\" XXX: Following are undefined in NetBSD at the time of writing:
107.\"
108.\".It Va trace_attr_t Ta trace stream attributes Ta -
109.\".It Va trace_event_id_t Ta trace event type Ta -
110.\".It Va trace_event_set_t Ta trace event type set Ta -
111.\".It Va trace_id_t Ta trace stream ID Ta -
112.It Va uid_t Ta user IDs Ta Xr setuid 2
113.It Va useconds_t Ta time in microseconds Ta Xr usleep 3
114.El
115.Pp
116In addition, when included in user applications,
117.In sys/types.h
118includes
119.In pthread.h ,
120and thus it defines also the types used in the
121.Tn POSIX
122Threads Library,
123.Xr pthread 3 .
124.Pp
125Each described type may vary across machines and operating systems.
126Only the following properties are guaranteed by the
127.St -p1003.1-2001
128standard:
129.Bl -enum -offset indent
130.It
131The type
132.Em ssize_t
133is capable of storing integer values at least in the range [\-1,
134.Dv SSIZE_MAX ] .
135.It
136The type
137.Em useconds_t
138is an unsigned integer capable of storing
139values at least in the range [0, 1000000].
140.It
141The type
142.Em suseconds_t
143is a signed integer capable of storing
144values at least in the range [\-1, 1000000].
145.It
146The
147.Em time_t
148and
149.Em clock_t
150types are either integers or real-floating types.
151.It
152The following types are integers:
153.Em gid_t ,
154.Em id_t ,
155.Em mode_t ,
156.Em nlink_t ,
157and
158.Em uid_t .
159.It
160The following types are signed integers:
161.Em blkcnt_t ,
162.Em blksize_t ,
163.Em off_t ,
164.Em pid_t ,
165and
166.Em ssize_t .
167.It
168The following types are unsigned integers:
169.Em fsblkcnt_t ,
170.Em fsfilcnt_t ,
171.Em ino_t ,
172and
173.Em size_t .
174.El
175.Ss NetBSD-specific Types
176In addition to the standard types,
177.In sys/types.h
178defines some data types specific to
179.Nx .
180These are mostly used in the kernel.
181A portable implementation should not rely
182on these types to be available in other systems.
183Examples include:
184.Bl -column -offset indent \
185"suseconds_t " "synonym for uint64_t   " "getdevmajor(3) "
186.It Sy Type Ta Sy Typical use Ta Sy Example
187.It Va cpuid_t Ta CPU IDs Ta Xr cpuset 3
188.It Va daddr_t Ta disk address Ta Xr buffercache 9
189.It Va devmajor_t Ta major device number Ta Xr getdevmajor 3
190.It Va lwp_t Ta typedef of Va struct lwp Ta Xr kthread 9
191.It Va u_quad_t Ta synonym for Va uint64_t Ta Xr strtouq 3
192.El
193.Pp
194It can be noted that the standard
195.Dq C99 types
196described in
197.Xr stdint 3
198are preferred to the older fixed size integer types prefixed with an
199.Dq u_
200(in other words,
201.Va uint32_t
202should be used instead of
203.Va u_int32_t ) .
204.Sh SEE ALSO
205.Xr param 3 ,
206.Xr stdbool 3 ,
207.Xr stddef 3 ,
208.Xr stdint 3 ,
209.Xr stdlib 3 ,
210.Xr unistd 3
211.Sh STANDARDS
212The
213.In sys/types.h
214header conforms to
215.St -p1003.1-2001
216with respect to the described standard types.
217.Sh HISTORY
218The
219.In sys/types.h
220header first appeared in
221.At v7 .
222In the current form the header appeared in
223.Nx 0.9 .
224