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Anonymous Archived
syscall of the day: time No.108737793
File: 1773508469045851.jpg (388 KB, 850x850)
388 KB JPG
syscall of the day: time No.108737793 Archived
previous: >>108730420

#define __NR_time                    201

https://man7.org/linux/man-pages/man2/time.2.html

tl;dr:
get the time

wow, back to a one syscall day. how exciting!
this one's pretty neat in a few ways. one, it often doesn't even call into the kernel, instead opting for the vdso. the vdso itself it worth reading about if you're not already familiar: https://man7.org/linux/man-pages/man7/vdso.7.html
it's quite interesting
as someone mentioned a few threads back, the posix standard explicitly ignores leap seconds. rather interesting choice, but i guess it's mostly understandable given machine limitations
beyond this, i found the error section amusing
       Error returns from this system call are indistinguishable from
       successful reports that the time is a few seconds before the
       Epoch, so the C library wrapper function never sets errno as a
       result of this call.

also, the part right below this about how it can never fail seems to conflict with the part about how it can fail with EOVERFLOW, but hey, what do i know?

relevant resources: 
man man

man syscalls

https://man7.org/linux/man-pages/
https://linux.die.net/man/
https://elixir.bootlin.com/linux/
https://elixir.bootlin.com/musl/
https://elixir.bootlin.com/glibc/
>>
Anonymous
 No.108738635
No.108738635
bampu
>>
Anonymous
 No.108738798
No.108738798
>>108737793
>the vdso itself it worth reading about if you're not already familiar: https://man7.org/linux/man-pages/man7/vdso.7.html
Doing that right now, thank you syscall anon and good thread as usual
>>
Anonymous
 No.108739164
No.108739164
>>108737793
Upboat for better image than usual
>>
Anonymous
 No.108739244
No.108739244
>>108737793
cute fleshlight
>>
Anonymous
 No.108739519
No.108739519
File: file.png (196 KB, 346x417)
196 KB PNG
>>108739244
is she really?
>>
Anonymous
 No.108739718
No.108739718
>>108738798
what are your thoughts?
glad you enjoy the threads, though
>>108739244
she is LITERALLY me
>>
Anonymous
 No.108740530
No.108740530
>>108739718
are you a fleshlight
>>
Anonymous
 No.108740733
No.108740733
>>108740530
.... maybe
>>
Anonymous
 No.108740822
No.108740822
>>108740733
damn, must be nice
>>
Anonymous
 No.108741399
No.108741399
Is this syscall limited to 32 bits on i386? Looks that way.
>>
Anonymous
 No.108741617
No.108741617
>>108740822
could be worse i guess
>>
Anonymous
 No.108742023
No.108742023
>>108739718
You are not a girl.
>>
Anonymous
 No.108742518
No.108742518
>>108739718
You are a girl.
>>
Anonymous
 No.108742522
No.108742522
File: sarah-415177-normal.jpg (44 KB, 355x500)
44 KB JPG
>>108739718
post syscalls that are literally you
>>
Anonymous
 No.108742531
No.108742531
>>108739718
love u sycall anon
>>
Anonymous
 No.108742887
No.108742887
>time() and time_t
>ftime() and struct timeb
>gettimeofday() and struct timeval
>clock_gettime() and struct timespec
imagine taking so many iterations to make a usable time interface
oh and kernel internally uses nanoseconds int64

anyway interesting fact about clock_gettime: there are some virtual clocks in /dev (e.g. PTP clocks) that you can use in place of the CLOCK_REALTIME or CLOCK_MONOTONIC enum
it's not a file descriptor directly, but somehow derived from it, don't recall exactly how
>>
Anonymous
 No.108743960
No.108743960
>>108742023
yes i am
>>108742518
i know
>>108742522
most of the ones in pure love tier i think
https://desuarchive.org/g/thread/108323183/#108323759
maybe some in pure sex tier
i like pipe a lot, so that one definitely
>>108742531
ily2 anon
>>
Anonymous
 No.108745243
No.108745243
>>108730420
god, I wish xattrs had first-class file system support. You can't use them, because programmes will randomly strip then whenever you perform file operations, so they get rarely used, so no one extends support, and on and on the cycle goes.
They're super handy for any sort of user-facing media, such as large image repositories. Such collections work much better with tags than with hierarchies, think of boorus, but you can't really use native Linux tagging because again, programmes will randomly nuke your entire tag db.
>>
Anonymous
 No.108745312
No.108745312
>>108743960
Im gonna fill you with semen until you puke cum
>>
Anonymous
 No.108745934
No.108745934
>>108745312
giwtwm
>>
Anonymous
 No.108745958
No.108745958
>>108745934
Which one?
>>
Anonymous
 No.108746706
No.108746706
>>108745958
the one being filled obviously
>>
Anonymous
 No.108746916
No.108746916
>>108746706
wow cute there's two of us
>>
Anonymous
 No.108746960
No.108746960
>>108742887
Yeah, C's time interface is a hot mess.
>>
Anonymous
 No.108747469
No.108747469
>>108746706
>>108746916
that's gay unless you're a girl
>>
Anonymous
 No.108747525
No.108747525
>>108747469
Being a girl is pretty gay.
>>
Anonymous
 No.108747573
No.108747573
>>108747525
not true, you are not a girl but youre gay
>>
Anonymous
 No.108747716
No.108747716
>>108737793
>rather interesting choice,
Not a choice, it's a pure counter. "Seconds since the epoch" doesn't include anything else.
>>
Anonymous
 No.108749247
No.108749247
>>108747716
It was a choice to introduce discontinuities with UTC.
>>
Anonymous
 No.108749316
No.108749316
>vdso
interesting stuff, didn't know that.
>>
Anonymous
 No.108749636
No.108749636
>>108737793
Yesterday I was writing seccomp filters and caught syscalls I'd never heard of, the shmat family. I looked at the man page, and did not understand what it was for. I searched the internet, and still did not receive enlightenment. I then remembered these threads exist, and found it on the archives. It too did not explain why you would use it.
>>
Anonymous
 No.108751231
No.108751231
>>108749636
lmao
>>
Anonymous
 No.108753230
No.108753230
>>108749636
The only place I ever saw this being used was NTP sever communicating with GPSd. Basically NTP sever exposes some shm interface and any time source can connect to it, and the shared memory or something should have lower latency than socket communication or whatnot.

Ofcourse you can also pass fd over socket and share memory through that, like wayland does. So it's some SysV legacy way used by ancient software.
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