#include <sys/types.h>
基本系统数据类型
是Unix/Linux系统的基本系统数据类型的头文件，含有size_t，time_t，pid_t等类型。linux编程中经常用到的头文件。
NAMEsys/types.h – data typesSYNOPSIS#include <sys/types.h>DESCRIPTIONThe <sys/types.h> header shall include definitions for at least the following types:blkcnt_tUsed for file block counts.blksize_tUsed for block sizes.clock_tUsed for system times in clock ticks or CLOCKS_PER_SEC; see <time.h> .clockid_tUsed for clock ID type in the clock and timer functions.dev_tUsed for device IDs.fsblkcnt_tUsed for file system block counts.fsfilcnt_tUsed for file system file counts.gid_tUsed for group IDs.id_tUsed as a general identifier; can be used to contain at least a pid_t, uid_t, or gid_t.ino_tUsed for file serial numbers.key_tUsed for XSI interprocess communication.mode_t Used for some file attributes.nlink_tUsed for link counts.off_tUsed for file sizes.pid_tUsed for process IDs and process group IDs.size_t Used for sizes of objects.ssize_tUsed for a count of bytes or an error indication.suseconds_tUsed for time in microseconds.time_t Used for time in seconds.timer_tUsed for timer ID returned by timer_create().trace_attr_tUsed to identify a trace stream attributes object.trace_event_id_tUsed to identify a trace event type.trace_event_set_tUsed to identify a trace event type set.trace_id_tUsed to identify a trace stream.uid_tUsed for user IDs.useconds_tUsed for time in microseconds.All of the types shall be defined as arithmetic types of an appropriate length, with the following exceptions:key_tAdditionally:* mode_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.* time_t and clock_t shall be integer or real-floating types.
发现一种久违的感动。
