cc -pipe -O   -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations signal/sigqueue.c -o signal/sigqueue -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt  -lrt -lcrypt
signal/sigqueue.c:5:40: error: 'sigqueue' undeclared here (not in a function); did you mean 'sigevent'?
 int (*foo)(pid_t, int, union sigval) = sigqueue;
                                        ^~~~~~~~
                                        sigevent