HI I have around 200 subroutines (may be more) and I have compiled that program with windows. However, I need to recompile that code in LINUX platform. But whenever I try to compile that in linux I always get error. The common error I get is "undefined reference to main __". As a new user of linux platform I don't know what that means and how to fix it. This is the same code that runs on windows. 

Please help me asap. 

Thanks. 
Anjeep

Are you familiar with make files in Linux? I used CMake to compile the codes in Linux. I recently had to compile C codes to executables and fortran codes as a library. It worked for me. 

 HI BBCnews, 

Thanks for your reply. Its been just a couple of days I am working fortran in LInux environment. During a lot of search in the internet I knew a little about the make files but I don't know how to make one. I would appreciate if you could tell why I got that error "undefined reference to main_". Thanks.

Anjeep

this might help:

http://software.intel.com/en-us/articles/error-undefined-reference-to-main/

 HI bbcnews, 

Thanks for your reply. I have compiled all the individual files with -c  command and then used ifort *.o -o program then the program is created. However, when I try to run the program it gives the error "

forttl : No such file or directory
fortt1 : severed (29): file not found, unit 1

Acutally I have the input file on the same folder. I don't know why I am getting such error ? Any help is appeciated. 

Thanks.

Anjeep

 Hi bbcnews, 

I found the source of my error. Actually I didn't care LInux is case sensitive. When I changed the case of the input files then the program worked perfectly. In windows I didn't have any problem with case of the input files. Thanks.

Anjeep