Specifies the form and meaning of program units written in ADA. Its purpose is to promote the portability of ADA programs to a variety of data processing systems. This standard specifies the form of a program unit written in ADA, the effect of translating and executing such a program unit, the manner in which program units may be combined to form ADA programs, the predefined program units that a conforming implementation study must supply, the permissible variations within the standard and the manner in which they must be specified, those violations of the standard that a conforming implementation is required to detect and the effect of attempting to translate or execute a program unit containing violations and those violations of the standard that a conforming implementation is not required to detect.