Files
pcas/src/libCom/misc/shareLib.h
1996-11-02 01:30:51 +00:00

63 lines
1.6 KiB
C

/*
* Use compiler specific key words to set up shareable library
* external symbols and entry points
*
* Right now this is only necessary for WIN32 DLL,
* the approach should be general enough for future systems, however.
*
*
* USAGE:
*
* In header files, declare variables, classes and functions
* to be __exported__ like this:
*
* epicsShareAPI int a_func (int arg);
* epicsShareExtern int a_var;
* class epicsShareClass a_class;
*
* Usually the epicsShare... macros expand to
* "import this from a DLL" (on WIN32, on Unix it's a NOP)
*
* In the implementation file, however, you write:
*
* #include <other_stuff.h>
* #define epicsExportSharedSymbols
* #include <what_I_implement.h>
* ! no more "foreign" includes from here on !
*
* The point is: define epicsExportSharedSymbols exacly and only
* right before you include the prototypes for what you implement!
* This time the epicsShare... macros expand to
* "export this from the DLL that we are building" (again only on WIN32)
*
* 8-22-96 -kuk-
*/
#undef epicsShareExtern
#undef epicsShareClass
#undef epicsShareAPI
#ifdef WIN32
# if defined(_WINDLL) || defined(epicsExportSharedSymbols)
# define epicsShareExtern __declspec(dllexport) extern
# define epicsShareClass __declspec(dllexport)
# else
# define epicsShareExtern __declspec(dllimport) extern
# define epicsShareClass __declspec(dllimport)
# endif
/*
* Subroutine removes arguments
*/
# define epicsShareAPI __stdcall
#else
/* no WIN32 -> no import/export specifiers */
# define epicsShareExtern extern
# define epicsShareAPI
# define epicsShareClass
#endif