cc -O2 -pipe  -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sys_mman/mode_t.c -o sys_mman/mode_t -D_POSIX_C_SOURCE=202405L  -lm -lpthread 
sys_mman/mode_t.c:2:1: error: unknown type name 'mode_t'; did you mean '__mode_t'?
mode_t* foo;
^~~~~~
__mode_t
/usr/include/sys/_types.h:54:20: note: '__mode_t' declared here
typedef __uint32_t      __mode_t;       /* permissions */
                        ^
1 error generated.