Exploring Expect

Linking

Linking a program with the Expect library requires only naming the appropriate libraries. The Expect library is called libexpect.a and must be supplied when the program is linked. Assuming that it is installed in your system so that the linker can find it, the library is traditionally named from the command line as "-lexpect“.

For example, if your program is composed of the object files "foo.o" and "bar.o“, they can be linked together as:

cc foo.c bar.c -lexpect -ltcl

The Tcl library is listed here too. The Expect library “borrows” Tcl’s regular expression pattern matcher but nothing else. Rather than shipping yet another copy of the pattern matcher, it is easier just to link with the Tcl library. The Tcl library may be avoided entirely by supplying a replacement for the regular expression pattern matcher.

When the library is used with other languages, it may be desirable to replace the glob or regular expression pattern matchers with different ones. For example, another language may define regular expressions differently than Tcl. Using Tcl’s regular expressions with those of another language would be confusing. Unfortunately, there is no standard interface for pattern matchers. A simple solution is to replace calls to the pattern matchers with new calls that follow any of the interfaces used by the Expect library. Because these interfaces are likely to change, they are not formally documented. However, the current interfaces are relatively trivial and should be easily understandable ...