Author: cnauroth
Date: Sat Aug 23 05:30:21 2014
New Revision: 1619967
URL: http://svn.apache.org/r1619967
Log:
HDFS-4852. libhdfs documentation is out of date. Contributed by Chris Nauroth.
Modified:
hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/site/apt/LibHdfs.apt.vm
Modified: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
URL:
http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt?rev=1619967&r1=1619966&r2=1619967&view=diff
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt (original)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt Sat Aug 23
05:30:21 2014
@@ -633,6 +633,8 @@ Release 2.6.0 - UNRELEASED
HDFS-6829. DFSAdmin refreshSuperUserGroupsConfiguration failed in
security cluster (zhaoyunjiong via Arpit Agarwal)
+ HDFS-4852. libhdfs documentation is out of date. (cnauroth)
+
Release 2.5.0 - 2014-08-11
INCOMPATIBLE CHANGES
Modified:
hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/site/apt/LibHdfs.apt.vm
URL:
http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/site/apt/LibHdfs.apt.vm?rev=1619967&r1=1619966&r2=1619967&view=diff
==============================================================================
---
hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/site/apt/LibHdfs.apt.vm
(original)
+++
hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/site/apt/LibHdfs.apt.vm
Sat Aug 23 05:30:21 2014
@@ -26,14 +26,17 @@ C API libhdfs
(HDFS). It provides C APIs to a subset of the HDFS APIs to manipulate
HDFS files and the filesystem. libhdfs is part of the Hadoop
distribution and comes pre-compiled in
- <<<${HADOOP_PREFIX}/libhdfs/libhdfs.so>>> .
+ <<<${HADOOP_HDFS_HOME}/lib/native/libhdfs.so>>> . libhdfs is compatible
with
+ Windows and can be built on Windows by running <<<mvn compile>>> within the
+ <<<hadoop-hdfs-project/hadoop-hdfs>>> directory of the source tree.
* The APIs
- The libhdfs APIs are a subset of: {{{hadoop fs APIs}}}.
+ The libhdfs APIs are a subset of the
+ {{{../../api/org/apache/hadoop/fs/FileSystem.html}Hadoop FileSystem APIs}}.
The header file for libhdfs describes each API in detail and is
- available in <<<${HADOOP_PREFIX}/src/c++/libhdfs/hdfs.h>>>
+ available in <<<${HADOOP_HDFS_HOME}/include/hdfs.h>>>.
* A Sample Program
@@ -55,24 +58,28 @@ C API libhdfs
fprintf(stderr, "Failed to 'flush' %s\n", writePath);
exit(-1);
}
- hdfsCloseFile(fs, writeFile);
+ hdfsCloseFile(fs, writeFile);
}
----
* How To Link With The Library
- See the Makefile for <<<hdfs_test.c>>> in the libhdfs source directory
- (<<<${HADOOP_PREFIX}/src/c++/libhdfs/Makefile>>>) or something like:
- <<<gcc above_sample.c -I${HADOOP_PREFIX}/src/c++/libhdfs
-L${HADOOP_PREFIX}/libhdfs -lhdfs -o above_sample>>>
+ See the CMake file for <<<test_libhdfs_ops.c>>> in the libhdfs source
+ directory (<<<hadoop-hdfs-project/hadoop-hdfs/src/CMakeLists.txt>>>) or
+ something like:
+ <<<gcc above_sample.c -I${HADOOP_HDFS_HOME}/include
-L${HADOOP_HDFS_HOME}/lib/native -lhdfs -o above_sample>>>
* Common Problems
The most common problem is the <<<CLASSPATH>>> is not set properly when
calling a program that uses libhdfs. Make sure you set it to all the
- Hadoop jars needed to run Hadoop itself. Currently, there is no way to
- programmatically generate the classpath, but a good bet is to include
- all the jar files in <<<${HADOOP_PREFIX}>>> and <<<${HADOOP_PREFIX}/lib>>>
as well
- as the right configuration directory containing <<<hdfs-site.xml>>>
+ Hadoop jars needed to run Hadoop itself as well as the right configuration
+ directory containing <<<hdfs-site.xml>>>. It is not valid to use wildcard
+ syntax for specifying multiple jars. It may be useful to run
+ <<<hadoop classpath --glob>>> or <<<hadoop classpath --jar <path>>>> to
+ generate the correct classpath for your deployment. See
+ {{{../hadoop-common/CommandsManual.html#classpath}Hadoop Commands
Reference}}
+ for more information on this command.
* Thread Safe
