Excel add-in and cygwin.dll

["Slavek F Kuzniar" <kuzniar_slavek at jpmorgan dot com>]

I am trying to find out if it is possible to build Excel Add-In that is using
Cygwin DLL and is capable of calling Excel functions through
xlcall32 library.
I believe someone on this list mentioned that you can do this only when
'-mno-cygwin' option is used so no cygwin1.dll is linked.

I tried building very simple XLL that can be loaded into Excel using Add-In
manager. When using 'no-cygwin' option
XLL loads fine. When I remove 'no-cygwin' option Excel crashes inside
cygwin1.dll. Even when I remove 'Excel4(...)' call which does not link
xlcall32.dll, add-in still crashes.

Following is the program, makefile, def file and 'cygcheck tst.xll' output in
case someone wants to try it. libxlcall32.a was created using
dlltool and hand-crafted .def file.


--------- tst.cpp
#include <windows.h>
#include <stdlib.h>
#include <xlcall.h>

#define DllImport __declspec(dllimport)
#define DllExport __declspec(dllexport)

/**     XLOPER string object. No virtual functions please.
        */
struct XLOPERString : public XLOPER
{
        /// Construct XLOPER string object
        XLOPERString(const char* txt)
        {
                if (txt)
                {
                        val.str = (char*) malloc(strlen(txt)+1);
                        strncpy(val.str + 1, txt, strlen(txt));
                        val.str[0] = strlen(txt);
                        xltype = xltypeStr;
                }
                else
                {
                        val.str = 0;
                }
        }
        /// Destroy XLOPER string object
        ~XLOPERString()
        {
                if (val.str)
                        free(val.str);
        }
};

/**     XLOPER integer object. No virtual functions please.
        */
struct XLOPERInt : public XLOPER
{
        /// Construct XLOPER integer object
        XLOPERInt(int ival)
        {
                xltype = xltypeInt;
                val.w = ival;
        }
};


#ifdef __cplusplus
extern "C" {
#endif
BOOL APIENTRY DllMain( HANDLE hDLL, DWORD dwReason, LPVOID lpReserved );
int DllExport WINAPI xlAutoOpen (void);
int DllExport WINAPI xlAutoAdd  (void);
#ifdef __cplusplus
}
#endif


BOOL APIENTRY DllMain( HANDLE hDLL, DWORD dwReason, LPVOID lpReserved )
{
        return TRUE;
}

int DllExport WINAPI xlAutoOpen(void)
{
        XLOPERString    ss("addin opened");
        XLOPERInt       ii(2);
        Excel4(xlcAlert, 0, 2, (LPXLOPER) &ss, (LPXLOPER) &ii);
        return 1;
}

int DllExport WINAPI xlAutoAdd(void)
{
        XLOPERString    ss("addin added");
        XLOPERInt       ii(2);
        Excel4(xlcAlert, 0, 2, (LPXLOPER) &ss, (LPXLOPER) &ii);
        return 1;
}


---------- makefile
C       = gcc
CC      = g++
CFLAGS  = -I. -g -mno-cygwin
CCFLAGS = -I. -g -mno-cygwin

LEX     = flex++
LFLAGS  = -Sflex_std.skl

LD      = dllwrap
LDFLAGS = -verbose --def tst.def -mno-cygwin -s -dll -mwindows -L../xlsdk -e
_DllMain@12

LIBS    = -lxlcall32

TARGET  = tst.xll

.SUFFIXES : .o .c .cpp .l


.c.o :
        ${C} ${CFLAGS} -c $<

.cpp.o :
        ${CC} ${CCFLAGS} -c $<

.l.cpp :
        ${LEX} ${LEXFLAGS} $<

OBJS    = \
        tst.o

${TARGET} : ${OBJS}
        ${LD} ${LDFLAGS} -s --dll -o $@ ${OBJS} ${LIBS}

clean :
        rm -rf *.o *~ doc ${TARGET}


----------- tst.def file
EXPORTS
        xlAutoOpen
        xlAutoAdd

----------- cygcheck output
Found: .\tst.xll
.\tst.xll
  c:/ct2/xlcall32.dll
    C:\WINNT\System32\KERNEL32.dll
      C:\WINNT\System32\ntdll.dll
  C:\WINNT\System32\msvcrt.dll

Use -h to see help about each section

----------- cygcheck output (with cygwin)
Found: .\tst.xll
.\tst.xll
  c:/ct2/xlcall32.dll
    C:\WINNT\System32\KERNEL32.dll
      C:\WINNT\System32\ntdll.dll
  C:\WINNT\System32\cygwin1.dll

Use -h to see help about each section







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