undefined reference to `MAIN__'

[Alex_L_]

Hi! My system: Debian 7.4 x86_64 / Intel Fortran Composer XE for Linux 2013 SP1 Update 2 / ifort version 14.0.2

After installation Intel Fortran Composer I used:  source /opt/intel/bin/compilervars.sh intel64

I'm trying to compile my *.f files with this command:

ifort -nofor-main -O2 -r8 -extend-source 80 -warn general *.f -o myprog

but this error occurs:

/opt/intel/composer_xe_2013_sp1.2.144/compiler/lib/intel64/libifcore.a(for_main.o): In function `main':
for_main.c:(.text+0x54): undefined reference to `MAIN__'

What's wrong here? Thanks in advance! Alex.

[Alex_L_]

Without -nofor-main i have:

/opt/intel/composer_xe_2013_sp1.2.144/compiler/lib/intel64/for_main.o: In function `main':
/export/users/nbtester/efi2linux_nightly/branch-14_0/20140121_010000/libdev/frtl/src/libfor/for_main.c:(.text+0x42): undefined reference to `MAIN__'

[Lorri_M_Intel]

Since you are creating a final executable, you need to have a main program, one where the execution can start.

Either you need to have a Fortran program that is the main program, or a C program.

It does not seem like you have either in this case.

                  --Lorri

[TimP]

Fortran main program is one beginning with PROGRAM (or, in f66 style, no procedure name declaration).  Without it, the linker doesn't have an entry point to start the program.

[John4]

You're actually telling the compiler to compile AND link.  To compile only, do:

-fort -c *.f

That will generate some *.o files.  Then, if you have a main program unit on the Fortran side (i.e., one with PROGRAM... END PROGRAM), you can link with:

ifort -o myprog *.o

If your main program unit is on the C-side, then you'll need something like:

ifort -c *.f

icc -o myprog *.c *.o