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Question

This error is inexplicably occurring. Here is the code and output:

timer.cpp:

#include "timer.h"
#include "SDL.h"
#include "SDL_timer.h"

void cTimer::recordCurrentTime()
{
    this->previous_t = this->current_t;
    this->current_t = SDL_GetTicks();
}

timer.h:

#include "SDL.h"
#include "SDL_timer.h"

class cTimer
{
private:
    int previous_t;
    int current_t;
    float delta_time;
    float accumulated_time;
    int frame_counter;
public:
    void recordCurrentTime();
    float getDelta();
    void incrementAccumulator();
    void decrementAccumulator();
    bool isAccumulatorReady();
    void incrementFrameCounter();
    void resetFrameCounter();
    int getFPS();
};

Compiler errors:

make
g++ -Wall -I/usr/local/include/SDL -c timer.cpp
timer.cpp: In member function ‘void cTimer::recordCurrentTime()’:
timer.cpp:6: error: ‘class cTimer’ has no member named ‘previous_t’
timer.cpp:6: error: ‘class cTimer’ has no member named ‘current_t’
timer.cpp:7: error: ‘class cTimer’ has no member named ‘current_t’
make: *** [timer.o] Error 1

Compiler errors after removing the #include "timer.h"

g++ -Wall -I/usr/local/include/SDL -c ctimer.cpp
ctimer.cpp:4: error: ‘cTimer’ has not been declared
ctimer.cpp: In function ‘void recordCurrentTime()’:
ctimer.cpp:5: error: invalid use of ‘this’ in non-member function
ctimer.cpp:5: error: invalid use of ‘this’ in non-member function
ctimer.cpp:6: error: invalid use of ‘this’ in non-member function
make: *** [ctimer.o] Error 1

Answer 1

Works for me. Are you sure you've got the right timer.h ? Try this:

cat timer.h

and verify that it's what you think it is. If so, try adding ^__^ at the beginning of your .h file and seeing if you get a syntax error. It should look something like this:

[/tmp]> g++ -Wall -I/tmp/foo -c timer.cpp
In file included from timer.cpp:1:
timer.h:1: error: expected unqualified-id before ‘^’ token

Answer 2

This seems very odd as

class cTimer
{
private:
    int previous_t;
    int current_t;
    float delta_time;
    float accumulated_time;
    int frame_counter;
public:
    void recordCurrentTime();
    float getDelta();
    void incrementAccumulator();
    void decrementAccumulator();
    bool isAccumulatorReady();
    void incrementFrameCounter();
    void resetFrameCounter();
    int getFPS();
};
void cTimer::recordCurrentTime()
{
    this->previous_t = this->current_t;
    this->current_t = SDL_GetTicks();
}

Compiles OK for me.

This suggests that the compiler think cTimer is different from what you've put in your header. So maybe its getting a definition of cTimer from another source file? For this to be the case your "timer.h" would have to not be gettting included correctly. So maybe the wrong timer.h.

A way to check this would be to save the compiler preprocessor output and search that for cTimer.

Another option might be to put a syntax error in your timer.h and make sure the compile fails.

Anyway hope this helps

Answer 3

Some compilers have their own timer.h, this is a name conflict.

Or it is a something else of bizarre bug...

Answer 4

Try renaming timer.h and timer.cpp to something more descriptive like ClassTimer.h and ClassTimer.cpp, maybe the compiler is linking another file named 'timer' since it is a very generic name. Also try this in timer.cpp:

void cTimer::recordCurrentTime(void)
{
    this->previous_t = this->current_t;
    this->current_t = SDL_GetTicks();
}

Edit: code edited