FoBiS.py

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Building a Library ​

FoBiS.py can build both static and shared Fortran libraries using the -mklib option.

Target required

Library building always requires specifying a -target file. Only the target and its dependencies are compiled and archived.

Source layout ​

src/
├── mylib.f90      ← library entry point (no `program` statement)
└── utils/
    └── helpers.f90

mylib.f90 might look like:

fortran
module mylib
  use helpers
  implicit none
  public :: compute
contains
  function compute(x) result(y)
    real, intent(in) :: x
    real :: y
    y = helpers_process(x)
  end function
end module mylib

Static library ​

bash
FoBiS.py build -t src/mylib.f90 -mklib static -o libmylib.a

Result: libmylib.a in the build directory, plus *.mod files in mod/.

Shared library ​

bash
FoBiS.py build -t src/mylib.f90 -mklib shared -o libmylib.so \
  -cflags " -c -fPIC" -lflags " -shared"

Result: libmylib.so in the build directory.

Using the library in another project ​

Once built, the library can be linked into another project. With -libs (full path):

bash
FoBiS.py build -libs /path/to/libmylib.a -i /path/to/mod/

Or with -ext_libs (by name):

bash
FoBiS.py build -ext_libs mylib -dlib /path/to/ -i /path/to/mod/

fobos examples ​

Static and shared variants ​

ini
[modes]
modes = static shared

[static]
compiler  = gnu
cflags    = -c -O2
build_dir = ./build/
obj_dir   = ./build/obj/
mod_dir   = ./build/mod/
src       = ./src/
target    = mylib.f90
mklib     = static
output    = libmylib.a

[shared]
compiler  = gnu
cflags    = -c -fPIC -O2
lflags    = -shared
build_dir = ./build/
obj_dir   = ./build/obj/
mod_dir   = ./build/mod/
src       = ./src/
target    = mylib.f90
mklib     = shared
output    = libmylib.so
bash
FoBiS.py build -mode static
FoBiS.py build -mode shared

Consumer project fobos ​

ini
[default]
compiler  = gnu
cflags    = -c -O2
src       = ./src/
build_dir = ./build/
libs      = /path/to/libmylib.a
include   = /path/to/mod/
target    = main.f90
output    = myapp

Volatile library (rebuild on change) ​

If the library is rebuilt externally (e.g. by CI), use -vlibs so that your project recompiles when the library changes:

bash
FoBiS.py build -vlibs /shared/build/libmylib.a -i /shared/build/mod/

See Volatile Libraries for details.

Interdependent build ​

For a more automated approach — where FoBiS.py build on the consumer project also rebuilds the library if its sources have changed — use -dependon:

ini
[default]
compiler = gnu
cflags   = -c -O2
src      = ./src/
target   = main.f90
dependon = ./libs/mylib/fobos:static

See Interdependent Projects for details.