An Input File with Extension by No Language Switch
If a language switch is not specified, but the input file includes a file-name extension,
gpre looks for the specified file and assumes the language is indicated by the extension.
For example, suppose the following command is processed:
gpre looks for a file called
gpre finds this file, it processes it as a C program and generates an output file called
gpre does not find this file, it returns the following error:
gpre: can’t open census.e