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authormatz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2008-12-29 09:07:20 +0000
committermatz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2008-12-29 09:07:20 +0000
commitd33298e52459045ddde4bae619a8da3c3cf7dbd6 (patch)
treec14bd8d6c2aec5109888c3410d888f997d7c18c0 /ext/io/wait
parent95327358ce9a2c7f2c2aab68cae4446c281a655e (diff)
* ext/io/wait/wait.c (io_nread): returns number of bytes available
for read. response to feature request #936 in [ruby-core:20917]. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@21169 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'ext/io/wait')
-rw-r--r--ext/io/wait/wait.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/ext/io/wait/wait.c b/ext/io/wait/wait.c
index 24e4141162e..b73c9af1ce3 100644
--- a/ext/io/wait/wait.c
+++ b/ext/io/wait/wait.c
@@ -44,6 +44,31 @@ EXTERN struct timeval rb_time_interval _((VALUE time));
/*
* call-seq:
+ * io.nread -> int
+ *
+ * Returns number of bytes that can be read without blocking.
+ * Returns zero if no information available.
+ */
+
+static VALUE
+io_nread(VALUE io)
+{
+ rb_io_t *fptr;
+ int len;
+ ioctl_arg n;
+
+ GetOpenFile(io, fptr);
+ rb_io_check_readable(fptr);
+ len = rb_io_read_pending(fptr);
+ if (len > 0) return len;
+ if (!FIONREAD_POSSIBLE_P(fptr->fd)) return INT2FIX(0);
+ if (ioctl(fptr->fd, FIONREAD, &n)) return INT2FIX(0);
+ if (n > 0) return ioctl_arg2num(n);
+ return INT2FIX(0);
+}
+
+/*
+ * call-seq:
* io.ready? -> true, false or nil
*
* Returns true if input available without blocking, or false.
@@ -137,6 +162,7 @@ io_wait(int argc, VALUE *argv, VALUE io)
void
Init_wait()
{
+ rb_define_method(rb_cIO, "nread", io_nread, 0);
rb_define_method(rb_cIO, "ready?", io_ready_p, 0);
rb_define_method(rb_cIO, "wait", io_wait, -1);
}