It works ! Just needed to enforce 64 bits compatibility.

(My Mac Pro is a double Intel quad core, 2008 model, and OSX is 10.5).

For reference, I hence compile the library with:

% ifort -dynamiclib  -arch x86_64 try_it.f -o try_it.so

or 

% ifort -dynamiclib  -m64 try_it.f -o try_it.so

and also

% gfortran -dynamiclib -m64 try_it.f -o try_it.so

(gfortran does not recognize the "-arch" option.)

g95 doesn't recognize neither -arch nor -m64 : what would be the equivalent ?

(I like to use g95 in some cases).

The "file" command gives me now:

% file try_it.so

try_it.so: Mach-O 64-bit dynamically linked shared library x86_64

Thanx acer !
 

It works ! Just needed to enforce 64 bits compatibility.

(My Mac Pro is a double Intel quad core, 2008 model, and OSX is 10.5).

For reference, I hence compile the library with:

% ifort -dynamiclib  -arch x86_64 try_it.f -o try_it.so

or 

% ifort -dynamiclib  -m64 try_it.f -o try_it.so

and also

% gfortran -dynamiclib -m64 try_it.f -o try_it.so

(gfortran does not recognize the "-arch" option.)

g95 doesn't recognize neither -arch nor -m64 : what would be the equivalent ?

(I like to use g95 in some cases).

The "file" command gives me now:

% file try_it.so

try_it.so: Mach-O 64-bit dynamically linked shared library x86_64

Thanx acer !