NAME

sys/types.h - data types

SYNOPSIS

#include <sys/types.h>

DESCRIPTION

The <sys/types.h> header includes definitions for 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 a gid_t.

ino_t

Used for file serial numbers.

key_t

Used for 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_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 initialisation.

pthread_rwlock_t

Used for read-write locks.

pthread_rwlockattr_t

Used for read-write lock attributes.

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().

uid_t

Used for user IDs.

useconds_t

Used for time in microseconds.

All of the types are defined as arithmetic types of an appropriate length, with the following exceptions: key_t, pthread_attr_t, pthread_cond_t, pthread_condattr_t, pthread_key_t, pthread_mutex_t, pthread_mutexattr_t, pthread_once_t, pthread_rwlock_t and pthread_rwlockattr_t. Additionally, blkcnt_t and off_t are  extended signed integral types, fsblkcnt_t, fsfilcnt_t and ino_t are defined as  extended unsigned integral types, size_t is an unsigned integral type, and blksize_t, pid_t and ssize_t are signed integral types. The type ssize_t is capable of storing values at least in the range [-1, SSIZE_MAX].  The type useconds_t is an unsigned integral type capable of storing values at least in the range [0, 1,000,000]. The type suseconds_t is a signed integral type capable of storing values at least in the range [-1, 1,000,000].

There are no defined comparison or assignment operators for the types pthread_attr_t, pthread_cond_t, pthread_condattr_t, pthread_mutex_t, pthread_mutexattr_t, pthread_rwlock_t and pthread_rwlockattr_t.

APPLICATION USAGE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

None.