C - Implicit declaration of the function "pthread_timedjoin_np"

Question

I am porting a windows library to linux. I need to use timed join to wait for the thread to join in a specific timeout.

When I compile the library on Linux I am getting the warning

Implicit declaration of the function - pthread_timedjoin_np

I have included pthread.h and have compiled with -lpthread link. I know that pthread_timedjoin_np is a non-standard GNU function. The function first appeared in glibc in version 2.3.3. and somewhere in BCD v6.

I even checked the Man Page for Linux but got no help. How do I avoid this warning? Any help?

Edit-1: My system is RedHat 5.

is this c++ or c? If it is c++, use the new C++0x standard std::thread class and it will be portable without you having to worry about it and remove the c tag. If it is C, please remove the c++ tag. — Jonathan Henson, Feb 25 '14 at 12:37
Sorry, my answer was wrong. Check [here](http://stackoverflow.com/questions/7296963/gnu-source-and-use-gnu), is `_GNU_SOURCE` defined before any headers are included? You could also add it to the compiler command, `-D_GNU_SOURCE` — Collin, Feb 25 '14 at 13:25

Collin · Answer 1 · 2014-02-25T13:34:12.750

17

Make sure the #define _GNU_SOURCE is before any of the your headers are included. Macros are set up by <features.h>, which include various parts of the GNU C library. If you've included other headers before you define _GNU_SOURCE, <features.h> will have already been included and will have not seen _GNU_SOURCE.

Even easier, just define it with the compiler adding -D_GNU_SOURCE as a compiler flag.

edited Feb 25 '14 at 13:34

answered Feb 25 '14 at 13:21

Collin

11,977
2
46
60

@jparthj Can you show your code (at least where you're including headers) and the command you're using to compile this file? – Collin Feb 27 '14 at 15:27
2

@Collin, I have had the same issue and your answer solves it !! Thanks. As you said, `#define _GNU_SOURCE` MUST be before any of headers included. – ogs Feb 05 '16 at 10:15

C - Implicit declaration of the function "pthread_timedjoin_np"

1 Answers1