I'm currently working on a Fortran program at work: a post-processing tool that takes climate data, in NetCDF format, and outputs in CMOR2 format (a NetCDF variant with climate conventions). So, it links against netcdf and cmor.

Now in HPC and climate in particular, codes are typically linked statically: partially for robustness, but mostly for speed (more on which later). So, I'd like to link this statically, as I have tens of terabytes of data to process. Now, mostly I've been linking using pkg-config:

  gfortran -o nemo-rewriter nemo-rewriter.f90 `pkg-config --libs --cflags nemo cmor`

pkg-config assembles the libraries. For dynamic libraries, the netcdf and cmor libraries are themselves linked to dependencies. But in the static case, all dependencies need to be on the link line, which is more complex. Never mind, it should be possible with:

  gfortran -static -o nemo-rewriter nemo-rewriter.f90 `pkg-config --static --libs --cflags nemo cmor`

This should work by assembling all the required static libraries, via pkg-config dependencies. Unfortunately not every package has a .pc file, and so this fails: As of version 4.1 NetCDF allows a URL instead of a file to read, and hence depends on curl to retrieve the file. Curl has no pkg-config .pc file describing its libraries, and it fails.

Never mind, lets assemble the static libraries by hand. Debian provides static versions of libraries in the -dev packages. Can I assemble a statically-linked program ? For this I need:

• NetCDF needs libnetcdff.a and libnetcdf.a directly.
• NetCDF needs HDF5: libnethdf5_hl.a and libhdf5.a for version 4 files.
• CMOR2 needs: libcmor2.a
• CMOR2 depends on libudunits2.a, to convert between physical units.

Now here it gets interesting. To handle secure communications and authentication, curl has some complex dependencies. It has two versions. Pick the gnutls one for example:

• libgss.a for Generic Security Services.
• libgss needs libidn.a for Internationalized Domain names
• libgss needs libshishi.a for Kerberos
• libshishi.a needs libgpg-error.a
• libshishi.a needs libgnutls.a
• libshishi.a needs libtasn1.a
• libshishi.a needs libgcrypt.a
• libshishi.a needs libresolv.a
• libcurl.a needs libssl.a
• libcurl.a needs libssh2.a
• libcurl.a needs libldap_r.a
• libdlap_r.a needs liblber.a
• libldap_r.a needs libsasl2.a. Which access databases, so ...
• libsasl2.a needs libmysqlclient.a
• libsasl2.a needs libpq.a
• libsasl2.a needs libdb-4.8.a
• libsasl.a needs libsqlite.a
• libssl.a needs libcrypto.a
• libcrypto.a needs libz.a
• libcurl.a needs libdl.a
• libcurl.a needs libcom_err.a
• libcurl.a needs libkeyutils.a
• libcurl.a needs libgssapi_krb5, which is in dynamic form only
• libcurl.a needs libkrb5crypto, which has no static library

I may have missed some out, having stopped because there is no static implementation of Kerberos on Debian. But still, the idea that a simple little fortran proggie will statically link in four database libraries is silly. It appears to be no longer possible to simply statically link a program in Debian, and definitely not via pkg-config, because so many dependencies do not yet have configuration files.