I am trying to pass the cache data to Mapper-Reducer (implemented in c++, pipes) by using the option -Dmapred.cache.files=/input/file.txt. In the mapper code I am able to read the path of the cache file by using the function job->get("mapred.cache.files"). Function returning me the path as /input/file.txt along with the binary path. I have taken out the cache path as /input/file.txt and trying to open the file by using the file function fopen( /input/file.txt, "r" ) but it is always returning NULL. I am not sure actually where the things going wrong. Anybody can help me out here.