Imposing Line Numbers automatically in the C code

Hi folks,

Is it possible to impose line numbers automatically while writing C Code in Linux using "vi editor"...my requirement is the whenver I put a DEBUG message, I can say where exactly the control has reached.

Code:

---


#define DEBUG(arg...) \
                printf(arg)

int main()
{
          //at line number 20
          DEBUG("I am in Line number : %d\n", Line Number());  // and it gives me the output as "I am in Line number : 20

          //similarly at line number 30
          DEBUG("I am in Line number : %d\n", Line Number());  // and it gives me the output as "I am in Line number : 30
}

---

Please let me know the way to implement the same or else if Linux already supports any such command or function which can tell me exact line number whenever I call that.

Thanks,
Cavestine:)

Most compilers support the __LINE__ macro

Code:

---

DEBUG("I am in Line number : %d\n", __LINE__);

---

Why not just use a debugger though?

Edit: FYI: There are a few more, __FILE__ & __DATE__ etc, see your compiler manual.

ya thats gr8:)...
is there any other way out instead of using __LINE__ macro...

also what are the other system supported macros for the Linux which can be used:)...


ya sure...i would definitely refer the manual...thanx:)...

thanx:)...

Quote:

---

Originally Posted by cavestine

ya thats gr8:)...
is there any other way out instead of using __LINE__ macro...

also what are the other system supported macros for the Linux which can be used:)...

---

Sure, you can count the lines yourself - or write a little preprocessing program that replaces "$LINE$" with the line number - but what's the benefit of that. The __LINE__ macro is there for this particular purpose.

Many compilers also support __function__ (gcc for example) which gives the name of the function. I think MS has a different macro, __FUNC__ or some such.

--
Mats

You mean a pre-pre-processing program :)

If you don't want to use __LINE__ use a debugger or turn on line numbers in vi and add them yourself like matsp suggested.

hi matsp...thanx for ur point...but when I tried to know the function I am in, the macro __function__ is not working as expected:(...

Code:

---


#include <stdio.h>

#define DEBUG(arg...)  \
                    printf(arg)

void secondfunc()
{
        DEBUG("I am in %s\n", __function__);
}

int main()
{
        DEBUG("I am in %s\n", __function__);
        secondfunc();
}

---

Please let me know, is this the right way of using the __function__ macro. If possible, provide with an example:)

According to the manual GCC provides 2 macros relating to functions

__PRETTY_FUNCTION__
__FUNCTION__

* Note the uppercase, the first is the function, it's type and the types of it's parameters while the latter is just the function name.

Code:

---

DEBUG("I am in %s\n", __FUNCTION__);
DEBUG("I am in pretty %s\n", __PRETTY_FUNCTION__);

---

ya thats gr8:)...

but when I try both the MACROS, I get the same result...

Code:

---


#include <stdio.h>

#define DEBUG(arg...)  \
                printf(arg)

void secondfunc()
{
        DEBUG("I am in %s\n", __PRETTY_FUNCTION__);
}

int main()
{
        DEBUG("I am in %s\n", __FUNCTION__);
        secondfunc();
}

---

the output which I am getting is:

Code:

---


I am in main
I am in secondfunc

---

are both the macros same??

secondfunc is void (no type) and has no arguments I'd assume that's why, or your compiler doesn't support __PRETTY_FUNCTION__ and instead aliased __FUNCTION__

even if I change the return type to int and accept few arguments, the output remains same...

Code:

---


#include <stdio.h>

#define DEBUG(arg...)  \
                printf(arg)

int secondfunc(int x, int y)
{
        DEBUG("I am in %s\n", __PRETTY_FUNCTION__);
        return 0;
}

int main()
{
        DEBUG("I am in %s\n", __FUNCTION__);
        secondfunc(2, 3);
}

---

Now to be very clear, I tried this but the output remained same...

Code:

---


#include <stdio.h>

#define DEBUG(arg...)  \
                printf(arg)

int secondfunc(int x, int y)
{
        DEBUG("I am in %s\n", __PRETTY_FUNCTION__);
        DEBUG("I am in %s\n", __FUNCTION__);
        return 0;
}

int main()
{
        DEBUG("I am in %s\n", __PRETTY_FUNCTION__);
        DEBUG("I am in %s\n", __FUNCTION__);
        secondfunc(2, 3);
}

---

the output I received:

Code:

---


I am in main
I am in main
I am in secondfunc
I am in secondfunc

---

any idea y is it happennig...any conceptual issue??

The __PRETTY_FUNCTION__ macro seems to work differently in C++ (printing whole function prototype) but same as __FUNCTION__ in C programs (with MingW).

yes anon u r correct, in C++, the macro __PRETTY_FUNCTION__ gives the complete information about the function, including
1. name of function
2. return type and
3. data types of its arguments:)

Hmmm...:)