cc -O2 -pipe  -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sys_msg/msgrcv.c -o sys_msg/msgrcv -D_POSIX_C_SOURCE=202405L  -lm -lpthread 
sys_msg/msgrcv.c:11:11: error: incompatible function pointer types initializing 'ssize_t (*)(int, void *, size_t, long, int)' (aka 'long (*)(int, void *, unsigned long, long, int)') with an expression of type 'int (int, void *, size_t, long, int)' (aka 'int (int, void *, unsigned long, long, int)') [-Werror,-Wincompatible-function-pointer-types]
ssize_t (*foo)(int, void *, size_t, long, int) = msgrcv;
          ^                                      ~~~~~~
1 error generated.