[Mingw-users] linkage failure when template decls and defs are in separate files

[Robert M D. <bob...@us...>]

I'd like to keep template declarations and template definitions in separate
files; however, I encounter the following error when trying to compile and
link a simple example (taken from p. 351, Stroustrup 2000 The C++
Programming Language).

C:\MyC++SourceCode\Templates>mingw32-make
g++.exe -c driver.cc -o driver.o -Ic:/MinGW/include
-Ic:/MingGW/include/c++/3.2
  -ftemplate-depth-30  -Wno-deprecated  -s -ansi
g++.exe -c Out.cc -o Out.o -Ic:/MinGW/include  -Ic:/MingGW/include/c++/3.2
-fte
mplate-depth-30  -Wno-deprecated  -s -ansi
g++.exe driver.o Out.o -o pgm.exe -Lc:/MinGW/lib -Ic:/MinGW/include
-Ic:/MingGW
/include/c++/3.2  -ftemplate-depth-30  -Wno-deprecated  -s -ansi
driver.o(.text+0x34):driver.cc: undefined reference to `void
out<double>(double
const&)'
mingw32-make: *** [pgm.exe] Error 1


Perhaps I'm missing some compiler flags?  I'm sure the error is probably
embarassingly simple, but any help is greatly appreciated.

I'm using MinGW 2.0.0-3.  The following list includes the makefile and
source code:

makefile
**************************************************************************
CC   = g++.exe
LIBS =  -Lc:/MinGW/lib
INCS =  -Ic:/MinGW/include  -Ic:/MingGW/include/c++/3.2

# Flags for normal development
CXXFLAGS = -ftemplate-depth-30  -Wno-deprecated

CFLAGS = $(INCS)  $(CXXFLAGS)  -s -ansi

OBJ  = driver.o Out.o
TARGET  = pgm.exe

.PHONY: all all-before all-after clean clean-custom

all: all-before $(TARGET) all-after

clean: clean-custom
      rm -f $(OBJ) $(TARGET)


$(TARGET): $(OBJ)
      $(CC) $(OBJ) -o $(TARGET) $(LIBS) $(CFLAGS)

driver.o: driver.cc
      $(CC) -c driver.cc -o driver.o $(CFLAGS)

Out.o: Out.cc
      $(CC) -c Out.cc -o Out.o $(CFLAGS)


driver.cc
**************************************************************************
#include "Out.h"

int main() {

  double x = 55.;
  out(x);

  return 0;
}


out.h
**************************************************************************
template<class T_numtype>  void out(const T_numtype& t);


out.cc
**************************************************************************
#include "out.h"
#include <iostream>

export template<class T_numtype> void out(const T_numtype& t) {
  std::cout << t;
}


******************************************************************************

Bob Dorazio
United States Geological Survey
7920 NW 71 Street
Gainesville, Florida  32653
Phone:  (352) 378-8181 x373
Fax:    (352) 378-4956
Email:  bdo...@us...
Internet:  www.fcsc.usgs.gov