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
- [XSI]
![[Option Start]](../images/opt-start.gif)
Used for XSI interprocess communication. ![[Option End]](../images/opt-end.gif)
- 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.
- reclen_t
- Used for directory entry lengths.
- 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().
- 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
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, reclen_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.
-
[CX]
time_t shall be an integer type with a width (see <stdint.h>) of at
least 64 bits.
The type ssize_t shall be capable of storing values at least in the range [-1, {SSIZE_MAX}].
[XSI]
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