How To Implement Closures?

As I understand, closures could be unboxed using a generated trampoline, like
mov rax, qword 12345678ABCDEFh ; 10 bytes function address
jmp rax ; 2 bytes
payload times N db 0 ; closure environment

Won't that mess code cache?

>>2
but you can have write access at the start and after that remove it and give it exec access, right?

>>7
C99 sucks[1], every C standard[2], even C11[3] sucks but C still the best language

[1]: C++ style commends, inline functions, intermingled declarations and code, long long int, _Bool instead of bool, universal character names, tgmath.h without giving a standard way to implement it (fixed in C11 with the badly designed _Generic)
[2]: non-thread safe functions (ex strtok), unsafe functions (ex gets, sprintf, scanf), lack of good high level functions for dynamic memory handling (eg getline from POSIX [still shit but anyway], strdup, asprintf, etc...), everything in time.h, useless functions like printf (we have already fprintf) and getc/putc (we have fputc/fgetc), no atleast N-bit integer (except from [u]int_{least/fast}{8,16,32,64}_t), useless auto keyword
[3]: nigger_s, makes variable length arrays optional even in hosted implemetations, _Generic is badly designed, _Alignas, _Alignof instead of alignas, alignof, _Noreturn instead of noreturn, _Thread_local instead of thread_local, _Atomic instead of atomic, _Static_assert instead of static_Assert (it is also badly designed)