From: Frank Mori Hess <fmhess@speakeasy.net>
Date: Mon, 10 Jan 2005 00:46:28 +0000 (+0000)
Subject: added comedi_mark_buffer_written() (untested)
X-Git-Tag: v0_8_0~139
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=9f6b16e004a2545af7014dc9d4b07b94bd64c921;p=comedilib.git

added comedi_mark_buffer_written() (untested)
---

diff --git a/doc/comedilib.sgml b/doc/comedilib.sgml
index e491ce1..14e9a77 100644
--- a/doc/comedilib.sgml
+++ b/doc/comedilib.sgml
@@ -55,7 +55,7 @@ handbook
   <holder>David Schleef</holder>
  </copyright>
  <copyright>
-  <year>2001-2003</year>
+  <year>2001-2003, 2005</year>
   <holder>Frank Mori Hess</holder>
  </copyright>
  <copyright>
diff --git a/doc/funcref b/doc/funcref
index e60fd69..04e25e1 100644
--- a/doc/funcref
+++ b/doc/funcref
@@ -795,18 +795,38 @@ Description:
  are available in the streaming buffer is returned.  If there is
  an error, -1 is returned.
 
-Function: comedi_mark_buffer_read -- streaming buffer status
+Function: comedi_mark_buffer_read -- streaming buffer control
 Retval: int
 Param: comedi_t * device
 Param: unsigned int subdevice
 Param: unsigned int num_bytes
 Description:
  The function comedi_mark_buffer_read() is used on a subdevice
- that has a Comedi command in progress.  This function can be
+ that has a Comedi input command in progress.  It should only be used
+ if you are using a mmap() (as opposed 
+ to calling read() on the device file) to read data from Comedi's buffer, 
+ since Comedi will automatically keep track of how many bytes have been
+ transferred via read() calls.  This function is
  used to indicate that the next num_bytes bytes in the buffer
  are no longer needed and may be discarded.
  If there is an error, -1 is returned.
 
+Function: comedi_mark_buffer_written -- streaming buffer control
+Retval: int
+Param: comedi_t * device
+Param: unsigned int subdevice
+Param: unsigned int num_bytes
+Description:
+ The function comedi_mark_buffer_written() is used on a subdevice
+ that has a Comedi output command in progress.  It should only be used
+ if you are using a mmap() (as opposed to calling write() on the device 
+ file) to write data to Comedi's buffer, since Comedi
+ will automatically keep track of how many bytes have been 
+ transferred via write() calls.  This function is
+ used to indicate that the next num_bytes bytes in the buffer
+ are valid and may be sent to the device.
+ If there is an error, -1 is returned.
+
 Function: comedi_get_buffer_offset -- streaming buffer status
 Retval: int
 Param: comedi_t * device
diff --git a/include/comedilib.h b/include/comedilib.h
index 3ede497..81ef65e 100644
--- a/include/comedilib.h
+++ b/include/comedilib.h
@@ -171,6 +171,8 @@ int comedi_set_max_buffer_size(comedi_t *it, unsigned int subdev,
 int comedi_get_buffer_contents(comedi_t *it, unsigned int subdev);
 int comedi_mark_buffer_read(comedi_t *it, unsigned int subdev,
 	unsigned int bytes);
+int comedi_mark_buffer_written(comedi_t *it, unsigned int subdev,
+	unsigned int bytes);
 int comedi_get_buffer_offset(comedi_t *it, unsigned int subdev);
 
 #ifdef _COMEDILIB_DEPRECATED
diff --git a/lib/buffer.c b/lib/buffer.c
index 4b89542..b197c3e 100644
--- a/lib/buffer.c
+++ b/lib/buffer.c
@@ -84,7 +84,21 @@ int _comedi_mark_buffer_read(comedi_t *it, unsigned int subdev, unsigned int byt
 	bi.bytes_read = bytes;
 	ret = comedi_ioctl(it->fd, COMEDI_BUFINFO, (unsigned long)&bi);
 	__comedi_errno = errno;
-	if(__comedi_errno == EINVAL)__comedi_errno = EBUF_OVR;
+	if(__comedi_errno == EPIPE)__comedi_errno = EBUF_OVR;
+	return bi.buf_int_count - bi.buf_user_count;
+}
+
+EXPORT_ALIAS_DEFAULT(_comedi_mark_buffer_written,comedi_mark_buffer_written,0.7.23);
+int _comedi_mark_buffer_written(comedi_t *it, unsigned int subdev, unsigned int bytes)
+{
+	int ret;
+	comedi_bufinfo bi;
+
+	memset(&bi, 0, sizeof(bi));
+	bi.bytes_written = bytes;
+	ret = comedi_ioctl(it->fd, COMEDI_BUFINFO, (unsigned long)&bi);
+	__comedi_errno = errno;
+	if(__comedi_errno == EPIPE)__comedi_errno = EBUF_UNDR;
 	return bi.buf_int_count - bi.buf_user_count;
 }
 
diff --git a/lib/version_script b/lib/version_script
index 41578d5..0a67f04 100644
--- a/lib/version_script
+++ b/lib/version_script
@@ -80,3 +80,8 @@ v0.7.20 {
 		comedi_parse_calibration_file;
 
 } v0.7.19;
+
+v0.7.23 {
+	global:
+		comedi_mark_buffer_written;
+} v0.7.20;