DUP(3)

💖 DUP(3) — Library Functions Manual 💖

🌸 NAME 🌸

dup — duplicate an open file descriptor. bestie, it’s literally giving “same file, new descriptor” energy 💅

✨ SYNOPSIS ✨

#include <u.h>
#include <libc.h>

int dup(int oldfd, int newfd)

💅 DESCRIPTION 💅

Okay so picture this: you give dup a file descriptor called oldfd, and that descriptor is referring to an open file. dup returns a new file descriptor that refers to the same file. iconic behavior, no cap 🫶

If newfd is -1, the system chooses the lowest available file descriptor. Otherwise, dup will use newfd for the new file descriptor — and yes, it closes any old file associated with newfd 😭💖

🦋 SOURCE 🦋

/src/lib9/dup.c

🎀 DIAGNOSTICS 🎀

Sets errstr. that’s the diagnostic moment, bestie ✨

💀 BUGS 💀

To avoid name conflicts with the underlying system, dup is a preprocessor macro defined as p9dup; see intro(3). iykyk, the macro girlies know 💅

Sign-off time: the bottom-of-page footer is literally just DUP(3) — that’s the cute footer energy, mwah 💋✨