c - In function `_start': (.text+0x20): undefined reference to `main'

i know this has been asked before but I seem to cannot find the answer that i need. Compiler seems to work fine with other codes so I believe the problem is in the code. I'm using eclipse and first I thought it may be a configuration error but when I try in the command line it's the same error.i know this has been asked before but I seem to