sys_types.h(0P)

📦 version 2017a, in alpine 3.22, alpine 3.23, alpine 3.24, arch rolling, nixpkgs unstable, opensuse-leap 16.0

🌸 sys_types.h(0P) — the POSIX Programmer's Manual one 🌸

okay bestie, so this is sys_types.h(0P) from the POSIX Programmer's Manual 💖 buckle up, we're talking about types and honestly? it's giving foundational.

⚠️ PROLOG ⚠️

so like. this manual page is part of the POSIX Programmer's Manual. but here's the tea: the Linux implementation of this interface may differ (so pls go consult the corresponding Linux manual page for the deets on Linux behavior), or — and this is the part that hurts 😭 — the interface might not even be implemented on Linux at all. vibe check accordingly.

✨ NAME ✨

sys/types.h — data types. that's it. that's the whole name. iconic minimalism.

🎀 SYNOPSIS 🎀

#include <sys/types.h>

literally just include it and you're in. no cap. 🫶

💅 DESCRIPTION 💅

the <sys/types.h> header shall define at least the following types, and bestie, there's a LOT of them:

  • blkcnt_t — for file block counts 📦
  • blksize_t — for block sizes 📏
  • clock_t — for system times, measured in clock ticks or CLOCKS_PER_SEC; go peek at <time.h> for the lore ⏰
  • clockid_t — the clock ID type used in the clock and timer functions 🕰️
  • dev_t — for device IDs 🔌
  • fsblkcnt_t — for file system block counts 🗂️
  • fsfilcnt_t — for file system file counts 📁
  • gid_t — for group IDs 👥
  • id_t — a general identifier type; it can hold at least a pid_t, a uid_t, or a gid_t. she's versatile 💁‍♀️
  • ino_t — for file serial numbers 🔢
  • key_t — for XSI interprocess communication 🔑
  • mode_t — for some file attributes 🛠️
  • nlink_t — for link counts 🔗
  • off_t — for file sizes 📐
  • pid_t — for process IDs and process group IDs 👑
  • pthread_attr_t — identifies a thread attribute object 🧵
  • pthread_barrier_t — identifies a barrier 🚧
  • pthread_barrierattr_t — defines a barrier attributes object 🚧✨
  • pthread_cond_t — for condition variables 😴
  • pthread_condattr_t — identifies a condition attribute object 😴✨
  • pthread_key_t — for thread-specific data keys 🗝️
  • pthread_mutex_t — for mutexes 🔒
  • pthread_mutexattr_t — identifies a mutex attribute object 🔒✨
  • pthread_once_t — for dynamic package initialization 1️⃣
  • pthread_rwlock_t — for read-write locks 📖✍️
  • pthread_rwlockattr_t — for read-write lock attributes 📖✍️✨
  • pthread_spinlock_t — identifies a spin lock 🌀
  • pthread_t — identifies a thread 🧵👑
  • size_t — for sizes of objects 📦📦
  • ssize_t — for a count of bytes, or an error indication 🚨
  • suseconds_t — for time in microseconds ⚡
  • time_t — for time in seconds ⏳
  • timer_t — the timer ID returned by timer_create() ⏲️
  • trace_attr_t — identifies a trace stream attributes object 🔍
  • trace_event_id_t — identifies a trace event type 🔍✨
  • trace_event_set_t — identifies a trace event type set 🔍✨✨
  • trace_id_t — identifies a trace stream 🔍🌊
  • uid_t — for user IDs 🫵

fr fr, all of these types shall be defined as arithmetic types of an appropriate length, with these exceptions (the girlies that are not arithmetic types):

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. and time_t shall be an integer type. (they're a duo but not twins, iykyk 💫)

the type ssize_t shall be capable of storing values at least in the range [-1, {SSIZE_MAX}]. slay.

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. (we love a lookup moment 🕵️‍♀️)

🚩 heads up bestie: there are no defined comparison or assignment operators for the following types. so don't be out here comparing them like they're regular numbers, because they are NOT. periodt.
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. literally nothing. she said "no notes." 😌

💜 RATIONALE 💜

none. again. empty. the void. 🕳️✨

💜 FUTURE DIRECTIONS 💜

none. the future is, apparently, also quiet. 🔮

🌈 SEE ALSO 🌈

  • <time.h>
  • The System Interfaces volume of POSIX.1‐2017, confstr()
  • The Shell and Utilities volume of POSIX.1‐2017, getconf

okay so legally speaking, 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.

and here's the important bit, no cap: 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 .

and that's the whole page, bestie 🫶 this one came to you courtesy of IEEE/The Open Group, 2017 — mwah, go forth and #include responsibly 💖✨🎀

📦 where this page comes from