g++ libcygwin.a has an undefined reference
Larry Hall
cygwin-lh@cygwin.com
Tue May 18 16:31:00 GMT 2004
It's not really strange at all if you think about what you're asking the
compiler/linker to do. You've asked for an executable but provided no
entry point. Without "main()", there is no entry point so linking fails.
You can certainly compile what you have into an object file but an
executable requires a "main()". This is in the FAQ BTW.
Larry Hall http://www.rfk.com
RFK Partners, Inc. (508) 893-9779 - RFK Office
838 Washington Street (508) 893-9889 - FAX
Holliston, MA 01746
At 06:23 AM 5/18/2004, you wrote:
>Hello Al,
>
>thank you, it worked.
>i putted one at the end of the program just writing :
>
>}; // end of class
>int main(){}
>
>why does that work? I think thats strange.
>
>Regards Christian Rudiger
>
>Al Slater wrote:
>
>>Try putting a main function in the program!
>>Regards
>>Al
>>
>>>-----Original Message-----
>>>From: cygwin-owner@cygwin.com [mailto:cygwin-owner@cygwin.com] On Behalf Of Christian Rudiger
>>>Sent: 18 May 2004 11:09
>>>To: cygwin@cygwin.com
>>>Subject: g++ libcygwin.a has an undefined reference
>>>
>>>
>>>Hello there,
>>>
>>>i think the following problem has to do with cygwin, cause libcygwin.a has an undefined reference.
>>>I get the error message when compiling my little testprogram. The Programm and complete compiler messages follow:
>>>
>>>*************************************************************
>>>
>>>// reading a text file
>>>#include <iostream.h>
>>>#include <fstream.h>
>>>#include <stdlib.h>
>>>#include <string.h>
>>>
>>>using namespace std;
>>>
>>>class tryit {
>>>
>>> char *FILE_POSTFIX;// = new "myfile.txt"; <- ausserhalb nicht möglich
>>> string posti;
>>>public:
>>> int main (int argc, char** argv) {
>>>
>>> FILE_POSTFIX = new char[10]; //"Nodes.txt"; <- erst allocieren dann zuweisen !
>>> FILE_POSTFIX = "NODES.txt";
>>> char *filename = FILE_POSTFIX;
>>> char *output;
>>> ifstream in (filename) ;
>>> while (in){
>>> in >> output ;
>>> cout << output << endl;
>>> return 0;
>>> }
>>> }
>>>};
>>>
>>>*************************************************************
>>>
>>>g++ -v -Wall -Wno-deprecated tryme.cpp -o testthings.exe
>>>Reading specs from /usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/specs
>>>Configured with: /GCC/gcc-3.3.1-3/configure --with-gcc --with-gnu-ld --with-gnu-as --prefix=/usr --exec-prefix=/usr --sysconfdir=/etc --libdir=/usr/lib --libexecdir=/usr/sbin --mandir=/usr/share/man --infodir=/usr/share/info --enable-languages=c,ada,c++,f77,pascal,java,objc --enable-libgcj --enable-threads=posix --with-system-zlib --enable-nls --without-included-gettext --enable-interpreter --enable-sjlj-exceptions --disable-version-specific-runtime-libs --enable-shared --disable-win32-registry --enable-java-gc=boehm --disable-hash-synchronization --verbose --target=i686-pc-cygwin --host=i686-pc-cygwin --build=i686-pc-cygwin
>>>Thread model: posix
>>>gcc version 3.3.1 (cygming special)
>>> /usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/cc1plus.exe -quiet -v -D__GNUC__=3 -D__GNUC_MINOR__=3 -D__GNUC_PATCHLEVEL__=1 -D__CYGWIN32__ -D__CYGWIN__ -Dunix -D__unix__ -D__unix -idirafter /usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/../../../../include/w32api -idirafter /usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/../../../../i686-pc-cygw
>>in/lib/../../include/w32api
>>>tryme.cpp -D__GNUG__=3 -quiet -dumpbase tryme.cpp -auxbase tryme -Wall -Wno-deprecated -version -o /cygdrive/d/TMP/cc55YaOO.s
>>>GNU C++ version 3.3.1 (cygming special) (i686-pc-cygwin)
>>> compiled by GNU C version 3.3.1 (cygming special).
>>>GGC heuristics: --param ggc-min-expand=47 --param ggc-min-heapsize=32700 ignoring nonexistent directory "/usr/local/include" ignoring nonexistent directory "/usr/i686-pc-cygwin/include" ignoring duplicate directory "/usr/i686-pc-cygwin/lib/../../include/w32api"
>>>#include "..." search starts here:
>>>#include <...> search starts here:
>>> /usr/include/c++/3.3.1
>>> /usr/include/c++/3.3.1/i686-pc-cygwin
>>> /usr/include/c++/3.3.1/backward
>>> /usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/include
>>> /usr/include
>>> /usr/include/w32api
>>>End of search list.
>>>/usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/../../../../i686-pc-cygw
>>in/bin/as.exe
>>>--traditional-format -o /cygdrive/d/TMP/ccbPwKZW.o /cygdrive/d/TMP/cc55YaOO.s
>>> /usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/collect2.exe -Bdynamic --dll-search-prefix=cyg -o testthings.exe /usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/../../../crt0.o /usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/crtbegin.o -L/usr/lib/gcc-lib/i686-pc-cygwin/3.3.1 -L/usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/../../.. /cygdrive/d/TMP/ccbPwKZW.o -lstdc++ -lgcc -lcygwin -luser32 -lkernel32 -ladvapi32 -lshell32 -lgcc /usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/crtend.o
>>>/usr/lib/gcc-lib/i686-pc-cygwin/3.3.1/../../../libcygwin.a(lib
>>>cmain.o)(.text+0x7c): undefined reference to `_WinMain@16'
>>>collect2: ld returned 1 exit status
>>>make: *** [testthings.exe] Error 1
>>>
>>>Compilation exited abnormally with code 2 at Tue May 18 11:05:17
>>>
>>>
>>>Regards Christian Rudiger
>>>
>>>
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>>
>
>
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