gettid编译问题

gettid根据man手册

The gettid() system call first appeared on Linux in kernel 2.4.11.
       Library support was added in glibc 2.30.  (Earlier glibc versions did
       not provide a wrapper for this system call, necessitating the use of
       syscall(2).)

我查的glibc版本为：

ldd --version
ldd (GNU libc) 2.12

或者rpm -qi glibc

版本低于2.30，要使用的话得这样来：

#include <unistd.h>
#include <sys/syscall.h>
#define gettid() syscall(SYS_gettid)