[C++] Thread in Unix

[pieric27]

ora invece esercitandomi sulle code di messaggi in Linux mi dà un errore simile:
mycoda1.o: In function `main':
mycoda1.c.text+0xb2): undefined reference to `mq_open'
mycoda1.c.text+0xe5): undefined reference to `mq_getattr'
mycoda1.c.text+0x163): undefined reference to `mq_send'
mycoda1.c.text+0x19e): undefined reference to `mq_getattr'
mycoda1.c.text+0x1d9): undefined reference to `mq_close'
collect2: ld returned 1 exit status