sys_types.h man page

Prolog

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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
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
trace_attr_t

The following sections are informative.

See Also

<time.h>

The System Interfaces volume of POSIX.1‐2008, confstr()

The Shell and Utilities volume of POSIX.1‐2008, getconf

Info

2013 IEEE/The Open Group POSIX Programmer's Manual