> Hello All,

>          I understood that __FUNCTION__ is a preprocessor macro, which
> will substitute a file name. Similar to __FILE__ and __LINE__.

>          1) I have written a small code, only for __FUNCTION__ it
> prints as unknown why? What is the difference between __FILE__ and
> __FUNCTION__. When I comment #ifndef __FUNCTION block it prints the
> file name.
>          2) Where do I get a list of all the preprocessor macros.

> #include <stdio.h>
> #include <errno.h>

> #ifndef __LINE__
> #define __LINE__ 0
> #endif

> #ifndef __FILE__
> #define __FILE__ "Unknown"
> #endif

> #ifndef __FUNCTION__
> #define __FUNCTION__ "Unknown"
> #endif

> int assert(int bool, int line, char *file, char *fun)
> {
>         char mesg[100];
>         sprintf(mesg, "line: %d, file: %s, function: %s\nError ", line, file,
> fun);
>         if(bool){
>                 perror(mesg);
>                 errno = 0;
>         }
>         return 1;
> }
> int main()
> {
>         char info[50];
>         FILE *fp;

>         errno = 0;
>         fp = fopen("ex.dat", "r");
>         assert(fp == NULL, __LINE__ - 1, __FILE__, __FUNCTION__);

>         fp = fopen("t.c", "r");
>         assert(errno != 0, __LINE__, __FILE__, __FUNCTION__);
>         return 1;
> }

> bye,
> Sobhan