转载：https://blog.csdn.net/thesby/article/details/50512886
编译caffe-master时遇到的问题，__float128未定义，使用到cuda版本为7.5.18，boost为1.60，gcc为4.8，opencv为3.1，操作系统为ubuntu14.04，报错如下：
/usr/local/include/boost/config/suffix.hpp(510): error: identifier "__float128" is undefined 1 error detected in the compilation of "/tmp/tmpxft_00003571_00000000-16_threshold_layer.compute_50.cpp1.ii". make: *** [.build_release/cuda/src/caffe/layers/threshold_layer.o] Error 1 make: *** Waiting for unfinished jobs.... /usr/local/include/boost/config/suffix.hpp(510): error: identifier "__float128" is undefined 1 error detected in the compilation of "/tmp/tmpxft_00003578_00000000-16_batch_reindex_layer.compute_50.cpp1.ii". make: *** [.build_release/cuda/src/caffe/layers/batch_reindex_layer.o] Error 1 /usr/local/include/boost/config/suffix.hpp(510): error: identifier "__float128" is undefined 1 error detected in the compilation of "/tmp/tmpxft_0000357f_00000000-16_reduction_layer.compute_50.cpp1.ii". make: *** [.build_release/cuda/src/caffe/layers/reduction_layer.o] Error 1 /usr/local/include/boost/config/suffix.hpp(510): error: identifier "__float128" is undefined 1 error detected in the compilation of "/tmp/tmpxft_00003588_00000000-16_softmax_layer.compute_50.cpp1.ii". make: *** [.build_release/cuda/src/caffe/layers/softmax_layer.o] Error 1
问题在于boost到gcc.h头文件定义存在bug。解决方法就是：
sudo gedit /usr/local/include/boost/config/compiler/gcc.hpp
1
把第156行到内容由
#if defined(_GLIBCXX_USE_FLOAT128) && !defined(__STRICT_ANSI__)
1
修改为：
#if defined(_GLIBCXX_USE_FLOAT128) && !defined(__STRICT_ANSI__) && !defined(__CUDACC__)
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