sys_types.h
Section: POSIX Programmer's Manual (0P)
Updated: 2017
Page Index
PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
NAME
sys/types.h
--- data types
SYNOPSIS
#include <sys/types.h>
DESCRIPTION
The
<sys/types.h>
header shall define at least the following types:
- blkcnt_t
-
Used for file block counts.
- blksize_t
-
Used for block sizes.
- clock_t
-
Used for system times in clock ticks or CLOCKS_PER_SEC; see
<time.h>.
- clockid_t
-
Used for clock ID type in the clock and timer functions.
- dev_t
-
Used for device IDs.
- fsblkcnt_t
-
Used for file system block counts.
- fsfilcnt_t
-
Used for file system file counts.
- gid_t
-
Used for group IDs.
- id_t
-
Used as a general identifier; can be used to contain at least a
pid_t,
uid_t,
or
gid_t.
- ino_t
-
Used for file serial numbers.
- key_t
-
Used for XSI interprocess communication.
- mode_t
-
Used for some file attributes.
- nlink_t
-
Used for link counts.
- off_t
-
Used for file sizes.
- pid_t
-
Used for process IDs and process group IDs.
- pthread_attr_t
-
Used to identify a thread attribute object.
- pthread_barrier_t
-
Used to identify a barrier.
- pthread_barrierattr_t
-
Used to define a barrier attributes object.
- pthread_cond_t
-
Used for condition variables.
- pthread_condattr_t
-
Used to identify a condition attribute object.
- pthread_key_t
-
Used for thread-specific data keys.
- pthread_mutex_t
-
Used for mutexes.
- pthread_mutexattr_t
-
Used to identify a mutex attribute object.
- pthread_once_t
-
Used for dynamic package initialization.
- pthread_rwlock_t
-
Used for read-write locks.
- pthread_rwlockattr_t
-
Used for read-write lock attributes.
- pthread_spinlock_t
-
Used to identify a spin lock.
- pthread_t
-
Used to identify a thread.
- size_t
-
Used for sizes of objects.
- ssize_t
-
Used for a count of bytes or an error indication.
- suseconds_t
-
Used for time in microseconds.
- time_t
-
Used for time in seconds.
- timer_t
-
Used for timer ID returned by
timer_create().
- trace_attr_t
-
Used to identify a trace stream attributes object
- trace_event_id_t
-
Used to identify a trace event type.
- trace_event_set_t
-
Used to identify a trace event type set.
- trace_id_t
-
Used to identify a trace stream.
- uid_t
-
Used for user IDs.
All of the types shall be defined as arithmetic types of an appropriate
length, with the following exceptions:
pthread_attr_t
pthread_barrier_t
pthread_barrierattr_t
pthread_cond_t
pthread_condattr_t
pthread_key_t
pthread_mutex_t
pthread_mutexattr_t
pthread_once_t
pthread_rwlock_t
pthread_rwlockattr_t
pthread_spinlock_t
pthread_t
timer_t
trace_attr_t
trace_event_id_t
trace_event_set_t
trace_id_t
Additionally:
- *
-
mode_t
shall be an integer type.
- *
-
dev_t
shall be an integer type.
- *
-
nlink_t,
uid_t,
gid_t,
and
id_t
shall be integer types.
- *
-
blkcnt_t
and
off_t
shall be signed integer types.
- *
-
fsblkcnt_t,
fsfilcnt_t,
and
ino_t
shall be defined as unsigned integer types.
- *
-
size_t
shall be an unsigned integer type.
- *
-
blksize_t,
pid_t,
and
ssize_t
shall be signed integer types.
- *
-
clock_t
shall be an integer or real-floating type.
time_t
shall be an integer type.
The type
ssize_t
shall be capable of storing values at least in the range
[-1, {SSIZE_MAX}].
The type
suseconds_t
shall be a signed integer type capable of storing values at least in
the range [-1, 1000000].
The implementation shall support one or more programming environments
in which the widths of
blksize_t,
pid_t,
size_t,
ssize_t,
and
suseconds_t
are no greater than the width of type
long.
The names of these programming environments can be obtained using the
confstr()
function or the
getconf
utility.
There are no defined comparison or assignment operators for the
following types:
pthread_attr_t
pthread_barrier_t
pthread_barrierattr_t
pthread_cond_t
pthread_condattr_t
pthread_mutex_t
pthread_mutexattr_t
pthread_rwlock_t
pthread_rwlockattr_t
pthread_spinlock_t
timer_t
trace_attr_t
The following sections are informative.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
<time.h>
The System Interfaces volume of POSIX.1-2017,
confstr()
The Shell and Utilities volume of POSIX.1-2017,
getconf
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .