Eric Blake wrote:
> I've touched up your proposal, and done more testing with this.
Great, thanks!
I've done three more touch-ups:
- In the module description, prefer a lib_SOURCES augmentation to an
AC_LIBOBJ invocation when possible. In this case both are equivalent,
but AC_LIBOBJ has some restrictions that make lib_SOURCES a better
choice in general.
- Fix ASSERT expressions: recall that == has higher precedence than ? :.
- A little more structure in the tests file, to separate independent tests.
Bruno
--- lib/nonblocking.c.orig Thu Mar 31 13:06:41 2011
+++ lib/nonblocking.c Thu Mar 31 12:53:36 2011
@@ -48,6 +48,7 @@
return -1;
}
else
+ /* Win32 does not support non-blocking on regular files. */
return 0;
}
@@ -125,7 +126,7 @@
fcntl_flags = fcntl (desc, F_GETFL, 0);
if (fcntl_flags < 0)
return -1;
- if (!!(O_NONBLOCK & fcntl_flags) == value)
+ if (((fcntl_flags & O_NONBLOCK) != 0) == value)
return 0;
if (value)
fcntl_flags |= O_NONBLOCK;
--- lib/nonblocking.h.orig Thu Mar 31 13:06:41 2011
+++ lib/nonblocking.h Thu Mar 31 12:51:19 2011
@@ -26,6 +26,9 @@
- A write() call returns -1 with errno set to EAGAIN when it cannot
transport the requested amount of data (but at most one pipe buffer)
without blocking.
+ Non-blocking I/O is most useful for character devices, pipes, and sockets.
+ Whether it also works on regular files and block devices is platform
+ dependent.
There are three modern alternatives to non-blocking I/O:
- use select() or poll() followed by read() or write() if the descriptor
@@ -48,8 +50,7 @@
Return 0 upon success, or -1 with errno set upon failure.
The default depends on the presence of the O_NONBLOCK flag for files
or pipes opened with open() or on the presence of the SOCK_NONBLOCK
- flag for sockets. Regular files and directories cannot be made
- non-blocking; block and character devices depend on the system. */
+ flag for sockets. */
extern int set_nonblocking_flag (int desc, bool value);
--- modules/nonblocking.orig Thu Mar 31 13:06:41 2011
+++ modules/nonblocking Thu Mar 31 12:43:41 2011
@@ -12,9 +12,9 @@
sys_socket
configure.ac:
-AC_LIBOBJ([nonblocking])
Makefile.am:
+lib_SOURCES += nonblocking.c
Include:
"nonblocking.h"
--- tests/test-nonblocking.c.orig Thu Mar 31 13:06:41 2011
+++ tests/test-nonblocking.c Thu Mar 31 13:02:40 2011
@@ -31,27 +31,29 @@
main (void)
{
const char *file = "test-nonblock.tmp";
- int fd_file = creat (file, 0600);
+ int fd_file;
int fd_pipe[2];
int fd_sock;
bool sock_works = true;
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
- /* For now, we can't get nonblock status of windows sockets. */
+ /* For now, we can't get nonblocking status of windows sockets. */
sock_works = false;
#endif
+ fd_file = creat (file, 0600);
+
/* Assume std descriptors were provided by invoker. */
ASSERT (STDERR_FILENO < fd_file);
- /* Test regular files; setting nonblock on file is unspecified. */
+ /* Test regular files; setting nonblocking on file is unspecified. */
ASSERT (get_nonblocking_flag (fd_file) == 0);
ASSERT (set_nonblocking_flag (fd_file, false) == 0);
ASSERT (get_nonblocking_flag (fd_file) == 0);
ASSERT (close (fd_file) == 0);
ASSERT (unlink (file) == 0);
- /* Test directories; setting nonblock is unspecified. */
+ /* Test directories; setting nonblocking is unspecified. */
fd_file = open (".", O_RDONLY);
ASSERT (STDERR_FILENO < fd_file);
ASSERT (get_nonblocking_flag (fd_file) == 0);
@@ -84,32 +86,40 @@
/* Test sockets. */
fd_sock = socket (AF_INET, SOCK_STREAM, 0);
- ASSERT (get_nonblocking_flag (fd_sock) == sock_works ? 0 : -1);
+ ASSERT (get_nonblocking_flag (fd_sock) == (sock_works ? 0 : -1));
ASSERT (set_nonblocking_flag (fd_sock, true) == 0);
- ASSERT (get_nonblocking_flag (fd_sock) == sock_works ? 1 : -1);
+ ASSERT (get_nonblocking_flag (fd_sock) == (sock_works ? 1 : -1));
ASSERT (set_nonblocking_flag (fd_sock, false) == 0);
- ASSERT (get_nonblocking_flag (fd_sock) == sock_works ? 0 : -1);
+ ASSERT (get_nonblocking_flag (fd_sock) == (sock_works ? 0 : -1));
ASSERT (close (fd_sock) == 0);
#if SOCK_NONBLOCK
fd_sock = socket (AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
- ASSERT (get_nonblocking_flag (fd_sock) == sock_works ? 1 : -1);
+ ASSERT (get_nonblocking_flag (fd_sock) == (sock_works ? 1 : -1));
ASSERT (close (fd_sock) == 0);
#endif /* SOCK_NONBLOCK */
/* Test error handling. */
- errno = 0;
- ASSERT (get_nonblocking_flag (-1) == -1);
- ASSERT (errno == EBADF);
- errno = 0;
- ASSERT (set_nonblocking_flag (-1, false) == -1);
- ASSERT (errno == EBADF);
- errno = 0;
- ASSERT (set_nonblocking_flag (-1, true) == -1);
- ASSERT (errno == EBADF);
- errno = 0;
- ASSERT (set_nonblocking_flag (10000000, false) == -1);
- ASSERT (errno == EBADF);
+ {
+ errno = 0;
+ ASSERT (get_nonblocking_flag (-1) == -1);
+ ASSERT (errno == EBADF);
+ }
+ {
+ errno = 0;
+ ASSERT (set_nonblocking_flag (-1, false) == -1);
+ ASSERT (errno == EBADF);
+ }
+ {
+ errno = 0;
+ ASSERT (set_nonblocking_flag (-1, true) == -1);
+ ASSERT (errno == EBADF);
+ }
+ {
+ errno = 0;
+ ASSERT (set_nonblocking_flag (10000000, false) == -1);
+ ASSERT (errno == EBADF);
+ }
return 0;
}
--
In memoriam Selena Quintanilla <http://en.wikipedia.org/wiki/Selena>
