ISO/IEC 1539-1:2018

1. This document specifies the form and establishes the interpretation of programs expressed in the base Fortran language. The purpose of this document is to promote portability, reliability, maintainability, and efficient execution of Fortran programs for use on a variety of computing systems.
2. This document specifies
-  the forms that a program written in the Fortran language can take,
-  the rules for interpreting the meaning of a program and its data,
-  the form of the input data to be processed by such a program, and
-  the form of the output data resulting from the use of such a program.
3. Except where stated otherwise, requirements and prohibitions specified by this document apply to programs
rather than processors.
4. This document does not specify
-  the mechanism by which programs are transformed for use on computing systems,
-   the operations required for setup and control of the use of programs on computing systems,
-   the method of transcription of programs or their input or output data to or from a storage medium,
-   the program and processor behavior when this document fails to establish an interpretation except for the processor detection and reporting requirements in items (2) to (10) of 4.2,
-  the maximum number of images, or the size or complexity of a program and its data that will exceed the capacity of any particular computing system or the capability of a particular processor,
-  the mechanism for determining the number of images of a program,
-  the physical properties of an image or the relationship between images and the computational elements of a computing system,
-  the physical properties of the representation of quantities and the method of rounding, approximating, or computing numeric values on a particular processor, except by reference to ISO/IEC/IEEE 60559:2011 under conditions specified in Clause 17,
-  the physical properties of input/output records, files, and units, or
-  the physical properties and implementation of storage.