Missing pthread_mutexattr_t related constants

The compilation of following simple program fails

harshada@harshada-sangale:~/programs/c$ cat pthread_mutex.c
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <pthread.h>

int main()
{
        pthread_mutex_t m;
        pthread_mutexattr_t attr;

        pthread_mutexattr_init(&attr);
        pthread_mutexattr_setprotocol(&atrr, PTHREAD_PRIO_INHERIT);

        pthread_mutex_init(&m, &attr);
        return 0;
}

$ gcc -o pthread_mutex pthread_mutex.c -lpthread
pthread_mutex.c: In function ‘main’:
pthread_mutex.c:12:33: error: ‘atrr’ undeclared (first use in this function)
pthread_mutex.c:12:33: note: each undeclared identifier is reported
only once for each function it appears in
pthread_mutex.c:12:39: error: ‘PTHREAD_PRIO_INHERIT’ undeclared (first
use in this function)

 affects ubuntu