CODEWITHSUNDEEP
cline-numbers
Andrew
Andrew

Reputation: 1

Get line number of called function C

Is there a way to get the line number a function was called on in C without doing anything like below? The define can make it tedious after a while, having to use DP instead of { like usual, and hard to read; but the adding LINE as the first parameter to every function is just something I'm not willing to do.

    #include <stdio.h>
    #include <stdlib.h>
    #include <stdarg.h>
    #define println(x,...) printf(x,##__VA_ARGS__);printf("\n");
    /*
     *I would like to be able to replace __LINE__ with the line
     *each function was called on, or replace my DP define completely...
    */
    #ifdef _DEBUG_
        #define DP { println("%s:%d\t%s()",__FILE__,__LINE__,__FUNCTION__);
    #else
        #define DP {
    #endif
    void calledFunc()
    DP
        println("something something something");
    }
    void cFunc(int line)
    {
        println("%s:%d\t%s()",__FILE__,line,__FUNCTION__);
    }
    int main()
    DP
        calledFunc();
        /* ...and I don't want to have to do this all the time either*/
        cFunc(__LINE__);
    }

Upvotes: 0

Views: 1681

Answers (1)

Kirill Kobelev
Kirill Kobelev

Reputation: 10557

There is a good substitute for printing the line file name/number. It is called "LocationID" or LID.

LID is a number that is generated out the project wide counter. The latest value of the counter should be stored in the source file and checked in/out of the source control system like any other source file. The value of the counter can be scrambled. This forces its proper use. You use it like:

   #ifdef _DEBUG_
        #define DP(x, msg) println("%d: %s", x, msg);
   #endif

and in your source:

DP (3517, "Here we are.")

Advantage of the LIDs are:

  1. They are stable against modification of the source file, including renaming of the file/function.
  2. They are easy to find in the sources.
  3. Log file is much more compact and clear than with the file name and the function name.

I used this several times and it proved to be good. Generation and distribution of LID values among developers is an overhead, but the result is 10 times worth the price of this effort.

Upvotes: 1

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