75 lines
2.4 KiB
C
75 lines
2.4 KiB
C
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/*----------------------------------------------------------------------
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This simple C++ program demonstrates that static constructors (destructors)
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are invoked by Elk when loading a compiled C++ file (when exiting).
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o Compile the program with CC -c -I/usr/elk/include constructor.c, where
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/usr/elk is the toplevel directory of your Elk installation. Under
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Solaris 2.x (and SysVR4) you also have to specify -pic (-fpic for g++).
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o Invoke Elk and set the load-libraries to point to the C++ and the
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C library, e.g. type something like:
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(set! load-libraries "-L/usr/lang/SC2.0.1 -lC -lc")
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or
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(set! load-libraries "-R/usr/lang/lib -L/usr/lang/lib -lC -lc")
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or just
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(set! load-libraries "-lC -lc")
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depending on the platform and the place where the C++ library has
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been installed on your system. If you are using g++, you may have
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to mention both the g++ library and the gcc library.
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o Now "(load 'constructor.o)", observe the "invoking constructor" message,
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and evaluate "(test)", which should return 3. Terminate the interpreter
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and observe the "invoking destructor" message.
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o If you get a message from the linker complaining about `Text relocation
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remains against symbol _GLOBAL_.D.P_Test__Fv', you have probably run
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into a known bug in g++ on ELF-based systems (such as Solaris 2.x).
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In this case you have to link your C++ extensions with Elk statically
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or use a different C++ compiler.
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o If static constructors don't get called when loading compiled C++ files,
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your C++ compiler is probably using a naming convention for static
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constructors and destructors that is not anticipated by the current
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version of Elk.
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In this case, you may want to find out what kind of names are used
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(by applying "nm" to an object file) and add the name prefixes to
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the Init_Prefixes and Finit_Prefixes lists in src/stab.c in the Elk
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source tree. Then recompile Elk. Send me mail.
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----------------------------------------------------------------------*/
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#include "scheme.h"
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#include <iostream.h>
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class C {
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public:
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int i;
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C() {
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cerr << "[invoking constructor]" << endl;
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i = 3;
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}
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~C() { cerr << "[invoking destructor]" << endl; }
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};
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C c;
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Object P_Test() {
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return Make_Integer(c.i);
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}
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void elk_init_constructor() {
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Define_Primitive((Object (*)(...))P_Test, "test", 0, 0, EVAL);
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}
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void elk_finit_constructor() {
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cerr << "Goodbye." << endl;
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}
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