The code sample for this recipe is in Fortran and C, setting the stage for Chapter 9, Mixed-language Projects, where mixed-language programming will be discussed. The main program is a simple Fortran executable that calls a C function, print_info(), which will print the configuration information. It is worth noting that with Fortran 2003, the compiler will take care of name mangling (given a proper interface declaration of the C function), as seen in the simple example.f90 source file that we will use:

program hello_world

  implicit none

  interface
    subroutine print_info() bind(c, name="print_info")
    end subroutine
  end interface

  call print_info()

end program

The print_info() C function is defined in the template file, print_info.c.in. The variables starting and ending with @ will be substituted for their actual values at configure time:

#include <stdio.h>
#include <unistd.h>

void print_info(void) {
  printf("\n");
  printf("Configuration and build information\n");
  printf("-----------------------------------\n");
  printf("\n");
  printf("Who compiled | %s\n", "@_user_name@");
  printf("Compilation hostname | %s\n", "@_host_name@");
  printf("Fully qualified domain name | %s\n", "@_fqdn@");
  printf("Operating system | %s\n",
         "@_os_name@, @_os_release@, @_os_version@");
  printf("Platform | %s\n", "@_os_platform@");
  printf("Processor info | %s\n",
         "@_processor_name@, @_processor_description@");
  printf("CMake version | %s\n", "@CMAKE_VERSION@");
  printf("CMake generator | %s\n", "@CMAKE_GENERATOR@");
  printf("Configuration time | %s\n", "@_configuration_time@");
  printf("Fortran compiler | %s\n", "@CMAKE_Fortran_COMPILER@");
  printf("C compiler | %s\n", "@CMAKE_C_COMPILER@");
  printf("\n");

  fflush(stdout);
}