ESL provides the ability to call Dynamic Link Libraries (DLLs) of external functions and subroutines from within ESL programs. This chapter describes ESL's DLL functionality. ESL supports DLLs written in C, COBOL, and Pascal.

Most examples in this chapter are written in C. (Special notations for COBOL and Pascal appear where appropriate.)  We have tested ESL with various versions of Microsoft Visual Studio, including 6, 8, 10, 15 and 16, all using the C++ compiler. Other C compilers should also work with ESL, however, ESL cannot directly access the Managed Code environment as found in Microsoft’s .Net framework. Using the Interop switch within the C# assembler, it is possible to create a COM interface to the Managed Code, which can then be access from ESL via a C++ wrapper DLL.

Please contact the Help Desk if you need more information on accessing any Managed Code routines.