My reference https://blog.csdn.net/gulaixiangjuejue/article/details/86152598 tutorial, using behavior recognition in ubuntu16.04 iDT source, make to compile the source code in/usr/lib/GCC/x86_64 - - the gnu/Linux 4.8/../../../x86_64 - - the gnu/Linux crt1. O: : (in the function "_start". The text + 0 x20) : the "main" undefined reference
Collect2: error: ld returned 1 exit status this error, error and makefile contents below, could you tell me how to solve this?

CodePudding user response:

You may be compiled the file without saving, you press CTRL + s