C Namelist Facility

C Namelist Facility (CNL) is a package of software that supports the development of data-driven programs that utilize relatively free-form input files (e.g., text files) to control complex operations. The only comparable prior namelist facility is built into Fortran and does not support arrays or records. Newer computing languages, including C and Pascal, do not include built-in namelist facilities. A namelist facility enables a program to utilize relatively free-form input files that contain assignment statements that give values to variables. Variables to which values are not assigned in input files remain unchanged; therefore, it becomes possible to have default values set by static or dynamic initialization of values prior to namelist input and updating of values is optional. Because it is not required to include values of variables in namelist input files, new parameters can be added to evolving programs without rendering old namelist input files obsolete — provided that the new parameters have useful default values. It should be possible to execute CNL in any operating system that supports the ANSI C programming language. It has been executed in several variants of Unix and in VxWorks.