optional debugging

[Baloff]

Hello

I hope some one maybe point me to targeted reading for the issue at
hand, or explain how/why to fix this. thanks

in the code below, I need to conditionally use P(A) to allow debugging
code to be automatically stripped out by setting a command-line flag.

I did quite a bit of readying but confused as to how to implement what
I learned, CXXFLAGS which be default has the preprocessor options,
ifdef else endif usage...

******************************code**************** **************
#include <iostream>
using namespace std;

#ifdef DEBUG
#define P(A) cout << #A << ": " << (A) << endl;
#endif

int main() {
int a = 1, b = 2, c = 3;

//debugging starts
P(a); P(b); P(c);
P(a + b);
P((c - a)/b);
//debugging ends

} ///:~

******************************makefile************ ******************
CPP= g++
proj1: main.o
$(CPP) main.o -o proj1

#main.o: main.cpp
..SUFFIXES: .o .cpp
..cpp.o:
$(CPP) -c $<

[red floyd]

Baloff wrote:

Hello

I hope some one maybe point me to targeted reading for the issue at
hand, or explain how/why to fix this. thanks

in the code below, I need to conditionally use P(A) to allow debugging
code to be automatically stripped out by setting a command-line flag.

I did quite a bit of readying but confused as to how to implement what
I learned, CXXFLAGS which be default has the preprocessor options,
ifdef else endif usage...

******************************code**************** **************
#include <iostream>
using namespace std;

#ifdef DEBUG
#define P(A) cout << #A << ": " << (A) << endl; #else
#define P(A) ((void)0) #endif

int main() {
int a = 1, b = 2, c = 3;

//debugging starts
P(a); P(b); P(c);
P(a + b);
P((c - a)/b);
//debugging ends

} ///:~

******************************makefile************ ******************
CPP= g++ CPP=g++ -DDEBUG proj1: main.o
$(CPP) main.o -o proj1

#main.o: main.cpp
.SUFFIXES: .o .cpp
.cpp.o:
$(CPP) -c $<

[Baloff]

red floyd <no*****@here.dude> writes:

Baloff wrote:

Hello
I hope some one maybe point me to targeted reading for the issue at
hand, or explain how/why to fix this. thanks in the code below, I
need to conditionally use P(A) to allow debugging
code to be automatically stripped out by setting a command-line flag.
I did quite a bit of readying but confused as to how to implement
what
I learned, CXXFLAGS which be default has the preprocessor options,
ifdef else endif usage...
******************************code**************** **************
#include <iostream>
using namespace std;
#ifdef DEBUG
#define P(A) cout << #A << ": " << (A) << endl;

#else
#define P(A) ((void)0)

#endif
int main() {
int a = 1, b = 2, c = 3;
//debugging starts
P(a); P(b); P(c);
P(a + b);
P((c - a)/b);
//debugging ends
} ///:~
******************************makefile************ ******************
CPP= g++

CPP=g++ -DDEBUG

proj1: main.o
$(CPP) main.o -o proj1
#main.o: main.cpp
.SUFFIXES: .o .cpp
.cpp.o:
$(CPP) -c $<

who do you modify the makefile? to be able to issue $make debug

[Bernd Strieder]

Hello,

Baloff wrote:

#ifdef DEBUG
#define P(A) cout << #A << ": " << (A) << endl;
#endif
And what shall happen if DEBUG is not defined, if the macro P is not
defined, you will get syntax errors. Therefore:

#ifdef DEBUG
#define P(A) cout << #A << ": " << (A) << endl;
#else
#define P(A)
#endif

******************************makefile************ ******************
CPP= g++
proj1: main.o
$(CPP) main.o -o proj1

#main.o: main.cpp
.SUFFIXES: .o .cpp

..cpp.o:
$(CPP) -DDEBUG -c $<
# comment: no debug: $(CPP) -c $<

You violate a lot of conventions. Usually (at least in GNU make) there
is the variable CXX for the C++ compiler, and CXXFLAGS for flags for
the C++ compiler. If you use the builtin rule of make for C++, i.e. .cc
to .o, you may just write

proj1: main.o
$(CXX) $(CXXFLAGS) $(LDFLAGS) -o $@ $^

CXXFLAGS=-DDEBUG

Read the make manual about predefined rules and variables. There is a
predefined rule for compiling single .cc files to .o files. And there
is a predefined rule for compiling and linking a single .cc file to an
executable, i.e. proj1.cc to executable proj1. Everything else you have
to provide yourself in the makefile. And take care to not break
existing conventions, or nobody will be able to understand your
makefiles. The variable CPP is used for the preprocessor executable.

There are libraries out supporting logging, so search the Web to save
yourself from reinventing the wheel. Or do you do this for educational
purposes?

Bernd Strieder

[Baloff]

Bernd Strieder <st******@informatik.uni-kl.de> writes:

Hello,

Baloff wrote:

#ifdef DEBUG
#define P(A) cout << #A << ": " << (A) << endl;
#endif
And what shall happen if DEBUG is not defined, if the macro P is not
defined, you will get syntax errors. Therefore:

#ifdef DEBUG
#define P(A) cout << #A << ": " << (A) << endl;
#else
#define P(A)
#endif

******************************makefile************ ******************
CPP= g++
proj1: main.o
$(CPP) main.o -o proj1

#main.o: main.cpp
.SUFFIXES: .o .cpp

.cpp.o:
$(CPP) -DDEBUG -c $<
# comment: no debug: $(CPP) -c $<

You violate a lot of conventions. Usually (at least in GNU make) there
is the variable CXX for the C++ compiler, and CXXFLAGS for flags for
the C++ compiler. If you use the builtin rule of make for C++, i.e. .cc
to .o, you may just write

proj1: main.o
$(CXX) $(CXXFLAGS) $(LDFLAGS) -o $@ $^

CXXFLAGS=-DDEBUG

Read the make manual about predefined rules and variables. There is a
predefined rule for compiling single .cc files to .o files. And there
is a predefined rule for compiling and linking a single .cc file to an
executable, i.e. proj1.cc to executable proj1. Everything else you have
to provide yourself in the makefile. And take care to not break
existing conventions, or nobody will be able to understand your
makefiles. The variable CPP is used for the preprocessor executable.

There are libraries out supporting logging, so search the Web to save
yourself from reinventing the wheel. Or do you do this for educational
purposes?

I am going through the book "Thinking in C++" and following each
chapter and doing the exercises. but I will do my best to understand
instructions given on the newsgroup.


Bernd Strieder