Can C program be used without main function?

Question

From a Fortran Code, I intend to run a C code (to read a file) and fetch the read information. The main program is the Fortran code, which uses a function written in C to do the processing. In this C code, is it necessary to run a main function?

Answer 1

If Fortran only calls the C function, then the C code does not need a main() function.

The main() function of C is the program entry point. The system loads the .exe, transfers control to the startup code, which address is mentioned in the .exe file (the startup code is called crt , C run-time start-up). The run-time startup does initialization and then transfers control to the user code. The user code entry point is main() .

Since Fortran is the main program, no C run-time start-up is needed and so no main() is needed.

Answer 2

No, you don't need a main in your C code. The linker will use the main from the FORTRAN code, or rather, the FORTRAN equivalent of main , when linking your C functions to the FORTRAN program.