From 41d86a29051af9e3b5fe7e37bd4c0c0a18993767 Mon Sep 17 00:00:00 2001 From: zlg Date: Sun, 9 Jan 2022 16:46:25 -0800 Subject: Solve exercise 8-3: fflush and fclose --- ch8/8-03_fflush-and-fclose.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 ch8/8-03_fflush-and-fclose.c (limited to 'ch8') diff --git a/ch8/8-03_fflush-and-fclose.c b/ch8/8-03_fflush-and-fclose.c new file mode 100644 index 0000000..add2318 --- /dev/null +++ b/ch8/8-03_fflush-and-fclose.c @@ -0,0 +1,40 @@ +#include +#include +#include +#include +#include +#include "syscalls.h" +/* The C Programming Language: 2nd Edition + * + * Exercise 8-3: Design and write `_flushbuf`, `fflush`, and `fclose`. + * + * Notes: Not much guidance here, eh? :) We'll want to consult manpages. + * + * _flushbuf returns 0 on success, -1 on failure. + * fflush flushes a buffer, or *all* buffers + * fclose does housekeeping on _iob members so fds can be juggled + * + * Since work done in these exercises is predominantly in a header file, the + * final implementation is used for all exercises that rely on it. Attempts + * have been made to demonstrate *what* is being done, but it's difficult to do + * so without creating side effects inside the buffers themselves. Trust that + * if this file outputs its own source, everything is fine. + */ + +int main() { + /* Let's copy 8-2's exercise but get a different look on the buffer. */ + /* show the contents of buffers before and after flush */ + FILE *fp = fopen("8-03_fflush-and-fclose.c", "r"); + if (fp != NULL) { + char c; + while ((c = getc(fp)) != EOF) { + putchar(c); + } + /* fclose calls fflush */ + fclose(fp); + fclose(stdout); + } else { + puts("Could not open file for reading."); + } + return 0; +} -- cgit v1.2.3-54-g00ecf