+++ /dev/null
-/*
- * cat_noblock.c - open a file and display its contents, but exit rather than
- * wait for input.
- */
-#include <errno.h> /* for errno */
-#include <fcntl.h> /* for open */
-#include <stdio.h> /* standard I/O */
-#include <stdlib.h> /* for exit */
-#include <unistd.h> /* for read */
-
-#define MAX_BYTES 1024 * 4
-
-int main(int argc, char *argv[])
-{
- int fd; /* The file descriptor for the file to read */
- size_t bytes; /* The number of bytes read */
- char buffer[MAX_BYTES]; /* The buffer for the bytes */
-
-
- /* Usage */
- if (argc != 2) {
- printf("Usage: %s <filename>\n", argv[0]);
- puts("Reads the content of a file, but doesn't wait for input");
- exit(-1);
- }
-
- /* Open the file for reading in non blocking mode */
- fd = open(argv[1], O_RDONLY | O_NONBLOCK);
-
- /* If open failed */
- if (fd == -1) {
- if (errno = EAGAIN)
- puts("Open would block");
- else
- puts("Open failed");
- exit(-1);
- }
-
- /* Read the file and output its contents */
- do {
- int i;
-
- /* Read characters from the file */
- bytes = read(fd, buffer, MAX_BYTES);
-
- /* If there's an error, report it and die */
- if (bytes == -1) {
- if (errno = EAGAIN)
- puts("Normally I'd block, but you told me not to");
- else
- puts("Another read error");
- exit(-1);
- }
-
- /* Print the characters */
- if (bytes > 0) {
- for (i = 0; i < bytes; i++)
- putchar(buffer[i]);
- }
-
- /* While there are no errors and the file isn't over */
- } while (bytes > 0);
- return 0;
-}
--- /dev/null
+/*
+ * cat_nonblock.c - open a file and display its contents, but exit rather than
+ * wait for input.
+ */
+#include <errno.h> /* for errno */
+#include <fcntl.h> /* for open */
+#include <stdio.h> /* standard I/O */
+#include <stdlib.h> /* for exit */
+#include <unistd.h> /* for read */
+
+#define MAX_BYTES 1024 * 4
+
+int main(int argc, char *argv[])
+{
+ int fd; /* The file descriptor for the file to read */
+ size_t bytes; /* The number of bytes read */
+ char buffer[MAX_BYTES]; /* The buffer for the bytes */
+
+ /* Usage */
+ if (argc != 2) {
+ printf("Usage: %s <filename>\n", argv[0]);
+ puts("Reads the content of a file, but doesn't wait for input");
+ exit(-1);
+ }
+
+ /* Open the file for reading in non blocking mode */
+ fd = open(argv[1], O_RDONLY | O_NONBLOCK);
+
+ /* If open failed */
+ if (fd == -1) {
+ puts(errno == EAGAIN ? "Open would block" : "Open failed");
+ exit(-1);
+ }
+
+ /* Read the file and output its contents */
+ do {
+ /* Read characters from the file */
+ bytes = read(fd, buffer, MAX_BYTES);
+
+ /* If there's an error, report it and die */
+ if (bytes == -1) {
+ if (errno = EAGAIN)
+ puts("Normally I'd block, but you told me not to");
+ else
+ puts("Another read error");
+ exit(-1);
+ }
+
+ /* Print the characters */
+ if (bytes > 0) {
+ for (int i = 0; i < bytes; i++)
+ putchar(buffer[i]);
+ }
+
+ /* While there are no errors and the file isn't over */
+ } while (bytes > 0);
+
+ return 0;
+}
\begin{verbatim}
$ sudo insmod sleep.ko
-$ cat_noblock /proc/sleep
+$ cat_nonblock /proc/sleep
Last input:
$ tail -f /proc/sleep &
Last input:
Last input:
tail: /proc/sleep: file truncated
[1] 6540
-$ cat_noblock /proc/sleep
+$ cat_nonblock /proc/sleep
Open would block
$ kill %1
[1]+ Terminated tail -f /proc/sleep
-$ cat_noblock /proc/sleep
+$ cat_nonblock /proc/sleep
Last input:
$
\end{verbatim}
\samplec{examples/sleep.c}
-\samplec{examples/other/cat_noblock.c}
+\samplec{examples/other/cat_nonblock.c}
\subsection{Completions}
\label{sec:orgd9f9de4}