Compiling a program on Linux that calls POSIX timer functions (eg: timer\_create, timer\_settime) returns errors such as:

```

In function `foo':
timer.c:(.text+0xbb): undefined reference to `timer_create'
timer.c:(.text+0x187): undefined reference to `timer_settime'
collect2: ld returned 1 exit status

```

Which library do I need to link?