FCLOSE(3)

okay bestie, welcome to FCLOSE(3) from the Library Functions Manual — this is your stream-closing cheat sheet, and yes, she ate 💅✨

🎀 NAME 🎀

fclose, fdclose, fcloseall — close a stream. The whole trio, no cap.

🦋 LIBRARY 🦋

She lives in the Standard C Library (libc, -lc). Link her up with -lc, iykyk.

🌸 SYNOPSIS 🌸

#include <stdio.h>

int
fclose(FILE *stream);

int
fdclose(FILE *stream, int *fdp);

void
fcloseall(void);

✨ DESCRIPTION ✨

• fclose(FILE *stream) — dissociates the named stream from its underlying file or set of functions. If the stream was being used for output, any buffered data is written first, using fflush(3). Like, flush first, then close — main character energy fr fr.
• fdclose(FILE *stream, int *fdp) — equivalent to fclose(), except it does not close the underlying file descriptor. If fdp is not NULL, the file descriptor will be written to it. If the stream does not have an associated file descriptor, fdp will be set to -1. This type of stream is created with functions such as fmemopen(3), funopen(3), or open_memstream(3). Obsessed with the precision ngl.
• fcloseall(void) — calls fclose() on all open streams. She’s the “close everything” bestie 💀

💖 RETURN VALUES 💖

fcloseall() does not return a value. Periodt.

Upon successful completion, the fclose() and fdclose() functions return 0. Otherwise, EOF is returned and the global variable errno is set to indicate the error. Not the vibe, but that’s the contract 🫶

🔥 ERRORS 🔥

fdclose() fails if:

• [EOPNOTSUPP] — The stream does not have an associated file descriptor.

The fclose() and fdclose() functions may also fail and set errno for any of the errors specified for fflush(3).

The fclose() function may also fail and set errno for any of the errors specified for close(2).

💅 NOTES 💅

The fclose() and fdclose() functions do not handle NULL arguments in the stream variable; this will result in a segmentation violation. This is intentional. It makes it easier to make sure programs written under FreeBSD are bug free. This behaviour is an implementation detail, and programs should not rely upon it.

bestie, do not pass NULL and expect a cute little error message. She said no. Segfault city 😭

🌈 SEE ALSO 🌈

• close(2)
• fflush(3)
• fopen(3)
• setbuf(3)

⭐ STANDARDS ⭐

The fclose() function conforms to ISO/IEC 9899:1990 (“ISO C90”). Slay, standards icon 👑

🦄 HISTORY 🦄

The fcloseall() function first appeared in FreeBSD 7.0.

The fdclose() function first appeared in FreeBSD 11.0.

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later, bestie 🍓💜 — this page is from Debian, dated February 13, 2024. close those streams responsibly ✨