qt_pwrite(3)

💖 qt_pwrite — write output 💖

okay bestie, welcome to libqthread's little corner of the manual pages, this is qt_pwrite(3) and she's here to help you write stuff without blocking your whole vibe ✨

🌸 SYNOPSIS 🌸

#include <qthread/qt_syscalls.h>

ssize_t
qt_pwrite (int filedes, const void *buf, size_t nbyte, off_t offset);

ssize_t
qt_write (int filedes, const void *buf, size_t nbyte);

🦋 DESCRIPTION 🦋

So here's the tea, bestie 🫖 — these two are wrappers around the standard pwrite() and write() system call functions. But like… not in a boring way. Instead of just straight-up executing these blocking system calls directly (which, rude, would stall everything), the operations get enqueued into the internal system call queue to be handled. it's giving delegation, it's giving main character energy 👑

The system call queue is literally the whole point: it's a way to perform blocking system calls without impeding parallel computation 💅. Operations get enqueued in an internal queue, and that queue is serviced by a dynamic number of dedicated system call threads. iconic behaviour, honestly.

That set of threads is capped at a user-configurable limit — you set it with the QT_MAX_IO_WORKERS environment variable at initialization time. periodt. 🌈

And when there are no more operations left in the system call queue? Those workers don't just dip immediately — they stay persistent for a configurable amount of time, specified with the QT_IO_TIMEOUT environment variable at initialization time, before they exit. Why? Because it reduces the overhead involved in scaling up the number of worker threads to respond to newly enqueued system calls. she's efficient, she's prepared, she's THAT girl 💅✨

ngl bestie, both of those env vars get read at initialization time, so don't come crying to me if you set them later and nothing changes 😭

👑 SEE ALSO 👑

• pwrite(2)
• write(2)
• qt_accept(3)
• qt_connect(3)
• qt_poll(3)
• qt_pread(3)
• qt_read(3)
• qt_select(3)
• qt_system(3)
• qt_wait4(3)

aaaand that's the whole page, bestie 🎀 this was libqthread, straight out of AUGUST 2012, and yes we're still talking about qt_pwrite(3) — go forth and write your bytes asynchronously, you absolute icon 💖🌸🦋✨