prepro-cics-C.pl takes a C program as input, reads it line by line, and outputs a file with CICS instructions translated.

prepro-cics-C.pl performs only one pass and processes lines one by one. That is, it reads a line from source_file, outputs one or several lines, and then reads the next input line. This behavior enables it to be compatible for use as a preprocessor inside a compiler, but prohibits using the same file as input and output.