Re: gettid

[Jakub Wilk <jwilk@xxxxxxxxx>]

* Jonny Grant <jg@xxxxxxxx>, 2020-06-16, 12:36:
> SYNOPSIS         top
>   #define _GNU_SOURCE
>   #include <unistd.h>
>   #include <sys/types.h>
>
>   pid_t gettid(void);
>
> I can compile on Ubuntu without #define _GNU_SOURCE and call gettid()
>
> Maybe that line can be removed?

I don't think so. Here's what I get (with GCC 9):

  $ gcc test.c
  test.c: In function ‘main’:
  test.c:6:9: warning: implicit declaration of function ‘gettid’; did you mean ‘getgid’? [-Wimplicit-function-declaration]
      6 |  return gettid();
        |         ^~~~~~
        |         getgid

Prepending "#define _GNU_SOURCE" fixes the above.

--
Jakub Wilk

#include <unistd.h>
#include <sys/types.h>

int main(int argc, char **argv)
{
	return gettid();	
}