M2-Planet/known_issues.org

M2-Planet is subset of the C programming language.

Mostly by eliminating features that have yet to be proven useful in building compilers, linkers or assemblers.

AMD64 & AArch64 int initialization wrong

right now the code in cc_core.c in the function void program() simply doesn't output the correct output for AArch64 or AMD64. As the function should numerate the string global_token to determine if the leading 32bits should be 0 or 0xFFFFFFFF and output %0 or %0xFFFFFFFF accordingly.

example of failing code

#include #include #include

void write_string(char* s, FILE* f) { while(0 != s[0]) { fputc(s[0], f); s = s + 1; } }

void* empty = 0;

int main() { if (0 == empty) { write_string("Yes, is empty\n", stdout); } else { write_string("Oops, why not?\n", stdout); } return 0; }

multidimensional arrays return wrong results

example of failing code

#include

char** env_argv;

char getargchar(int n, int k) { return env_argv[n][k]; }

int main(int argc, char** argv) { env_argv = argv; fputc(getargchar(2, 4), stdout); return 0; }

run with: ./example 12345 abcdef ABCDEF

work around code

char getargchar(int n, int k) { char *tmp = env_argv[n]; return tmp[k]; }

Pointer arithmetic wrong

It isn't uncommon for complex C programs to iterate over an array using a pointer.

example of failing code

#include #include

void walk_array(char** array, char** array_end) { char** i = array; while(i < array_end) { fputs(i[0], stdout); fputc('\n', stdout); i = i + 1; } }

int main() { char** array = calloc(10, sizeof(char*)); array[0] = "hello"; array[1] = "world"; array[2] = "how"; array[3] = "are"; array[4] = "you"; array[5] = "today"; array[6] = "I"; array[7] = "am"; array[8] = "doing"; array[9] = "fine"; walk_array(array, array + 10); return 0; }

work around code

#include #include

// CONSTANT pointer_size sizeof(char*) #define pointer_size 1

void walk_array(char** array, char** array_end) { char** i = array; while(i < array_end) { fputs(i[0], stdout); fputc('\n', stdout); i = i + pointer_size; } }

int main() { char** array = calloc(10, sizeof(char*)); array[0] = "hello"; array[1] = "world"; array[2] = "how"; array[3] = "are"; array[4] = "you"; array[5] = "today"; array[6] = "I"; array[7] = "am"; array[8] = "doing"; array[9] = "fine"; walk_array(array, array + (10 * pointer_size)); return 0; }

struct initialization

M2-Planet doesn't support static initialization for structs yet.

Simply because time hasn't been made available for the effort.

Patches for adding support are welcome.

typedef doesn't work

M2-Planet doesn't support this function yet as the time for its development has not been allocated yet.

Patches are welcome

C style function pointers

M2-Planet supports universal function pointer FUNCTION Simply delete the typedef and the code works fine in M2-Planet

example of failing code

#include typedef int (*FUNCTION) ();

struct function { FUNCTION function; int arity; char* name; };

struct function fun_make_cell_;

int make_cell_ () { char* i = fun_make_cell_.name; while(0 != i[0]) { fputc(i[0], stdout); i = i + 1; } return fun_make_cell_.arity; }

int main () { fun_make_cell_.function = make_cell_; fun_make_cell_.arity = 2; fun_make_cell_.name = "bar\n"; fun_make_cell_.function(); }

logical and do not short circuit

Both sides of && evaluate because it hasn't been shown to be worth the effort of implementation of short-circuit logic

example of failing code

#include #include

int boom() { exit(EXIT_FAILURE); }

int main(int argc, char* argv) { if((0 == argc) && boom()) { fputs("impossible code\n", stderr); } return 0; }

work around code

#include #include

int boom() { exit(EXIT_FAILURE); }

int main(int argc, char* argv) { if(0 == argc) { if(boom())fputs("impossible code\n", stderr); } return 0; }