c++ - C++ 中的 sysconf() 错误

Question

我正在编译一个程序，它给出了以下错误。 gcc的版本是(GCC) 4.8.5 20150623 (Red Hat 4.8.5-4。

Utils.cpp: In static member function ‘static double Utils::process_mem_usage()’:
Utils.cpp:33:30: error: ‘_SC_PAGE_SIZE’ was not declared in this scope
  long page_size_kb = sysconf(_SC_PAGE_SIZE) / 1024; // if x86-64 is configured to use 2MB pages
                              ^
Utils.cpp:33:43: error: ‘sysconf’ was not declared in this scope
  long page_size_kb = sysconf(_SC_PAGE_SIZE) / 1024; // if x86-64 is configured to use 2MB pages

Answer 1

包括<unistd.h> , 其中_SC_PAGE_SIZE被定义并且 sysconf() 已声明。

参见 POSIX 规范:http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/unistd.h.html