Problems using Intel(R) compiler.. (novice user)

[nickschurch]

I seem to be having some problems using ifort to compile a gar-hydrodynamics program, called Zeus, written in Fortran90.

My computer runs duel Intel Core 2 processors (64 bit) and runs Scientific Linux (based on Fedora Core something-or-other). I have installed the intel Fortral compiler package appropriate for these processors (Intel 64 bit - file l_fc_p_10.1.015_intel64.tar.gz), and it seems to be working correctly (but I am far from an expert!).

When I attempt to build some of the libraries needed by the code I get the following error

[njs@Quezovercoatl nmlst]$ ifort namelist.f
namelist.f(2511): (col. 11) remark: LOOP WAS VECTORIZED.
namelist.f(2514): (col. 11) remark: LOOP WAS VECTORIZED.
namelist.f(1574): (col. 13) remark: LOOP WAS VECTORIZED.
namelist.f(1489): (col. 13) remark: LOOP WAS VECTORIZED.
namelist.f(1404): (col. 13) remark: LOOP WAS VECTORIZED.
namelist.f(1169): (col. 11) remark: LOOP WAS VECTORIZED.
namelist.f(1081): (col. 11) remark: LOOP WAS VECTORIZED.
namelist.f(998): (col. 11) remark: LOOP WAS VECTORIZED.
namelist.f(689): (col. 33) remark: LOOP WAS VECTORIZED.
namelist.f(689): (col. 33) remark: LOOP WAS VECTORIZED.
/compilers/intel/fortran/lib

/for_main.o: In function `main':
/export/users/nbtester/efi2linuxx86_nightly/branch-10_1/20080313_000000/libdev/frtl/src/libfor/for_main.c:(.text+0x26): undefined reference to `MAIN__'

Unfortunately I'm far from a fortran expert and have no real idea what this error is. Does anyone know what this means, or have any ideas/suggestions on how I should proceed?

[Steven_L_Intel1]

First, the "LOOP WAS VECTORIZED" messages are informational messages that tell you about optimizations. The real problem is that the source file you compiled does not contain a main program - perhaps it is is just a subroutine or function. When you use ifort without -c, it assumes you are building an executable and wants to find the main program. (This is no different from other compilers.)

If you are building a library, then use "ifort -c" to compile to a .o object. You would then need to use "ar" to construct the library.

[Kevin_D_Intel]

You will receive that error when trying to compile and link a Fortran source file that does not provide a Fortran MAIN program. I suspect namelist.f may contain only subprograms and thus is not expected to be compiled and linked.

To only compile namelist.f, add c option.

You will need to inspect the Zeus application build procedure (perhaps a makefile?) to know how the application compiles all the associated source files and then links the object files to create the resulting executable.