In addition to the instructions that are part of ARexx, like DO and SAY, ARexx also includes some functions for your use. Some are for use with File access, which will be discussed in a later article. Others are for string handling and comparison and other various functions.
Many functions return a value, even the simplest ones.
If you have no need for the return value of a function you don't need to use a variable to hold it, you can simple use the CALL instruction. Here are some mathematical functions and examples of their use. If the string is less then length then it is padded with the pad character which defaults to a blank space. If the number argument is supplied it returns the corresponding argument.