我想使用一些仅在该语言的最新版本中可用的 C++ 功能。问题是 Ubuntu 15.04 (Vivid Vervet) 安装了 4.9.2 并查看我从apt-get install gcc获得的输出：
Reading package lists... Done
Building dependency tree
Reading state information... Done
gcc is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n]
据说已经是最新版本了。我不明白为什么...