> Languages and APIs > The ILOG CPLEX Callable Library > ILOG CPLEX Programming Practices > Character Strings

You can pass character strings as parameters to various ILOG CPLEX routines, for example, as row or column names. The Interactive Optimizer truncates output strings usually at 18 characters. Routines from the Callable Library truncate strings at 255 characters in output text files (such as MPS, LP, and SOS text files) but not in binary SAV files. Routines from the Callable Library also truncate strings at 255 characters in names that occur in messages. Routines of the Callable Library that produce log files, such as the simplex iteration log file or the MIP node log file, truncate at 16 characters. The Callable Library routine CPXwritesol truncates character strings in binary solution files at 8 characters and in text solution files at 16 characters. Input, such as names read from LP and MPS files or typed interactively by the enter command, are truncated to 255 characters. However, it is not recommended that you rely on this truncation because unexpected behavior may result.