External Subprograms

Abstract

Most of the programs presented in this tutorial so far have consisted of only a main program, but beginning with this chapter and continuing through the three chapters following it, the focus will shift to the building blocks that are used to construct larger, more complicated programs. This chapter discusses those features of Fortran 90 subprograms that represent only rather modest extensions of the capabilities available in popular FORTRAN 77 implementations. The primary purpose of the chapter is to establish firmly the vocabulary and point of view that will provide the basis for subsequent presentation of more advanced topics. Very knowledgeable readers should be able to move quickly through this chapter, but the majority of readers can expect to encounter at least some material worthy of their consideration.