In PL/1, one or more character or bits concatenated to the right of a string to extend the string to a required length.For character strings, padding is with blanks; for bit strings, it is with zeros.

• 在程序设计语言pl/1中，并置在串右边以把串扩展到所需长度的一个或多个字符或者位。对于字符串，填充的是空格字符；对于位串，填充的是零。