x86_64-managarm-gcc -pthread -Wall -Wextra -Werror=implicit-function-declaration mqueue/mq_receive.c -o mqueue/mq_receive -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv -lintl -liconv mqueue/mq_receive.c: In function ‘main’: mqueue/mq_receive.c:101:14: error: implicit declaration of function ‘mq_send’ [-Wimplicit-function-declaration] 101 | if ( mq_send(mq, "foo", 3, 0) < 0 ) | ^~~~~~~