Some err handling and ++todo

src/win/win_stdio.c

@@ -168,6 +168,9 @@ FILE *fopen(const char *restrict name, const char *restrict mode) {
         } break;
     }
     HANDLE handle = CreateFileA(name, access, share, NULL, disp, flags, NULL);
+    if(handle == INVALID_HANDLE_VALUE) {
+        return NULL;
+    }
     FILE *stream = create_stream(handle, io_mode, bt_mode);
     void *buffer_data = malloc(BUFSIZ);
     stream->buffer = (stream_buffer_t) {1, _IOFBF, BUFSIZ, buffer_data};
@@ -406,6 +409,6 @@ int puts(char const *str) {
     return putchar('\n');
 }
 
-char *gets(char str) {
+char *gets(char *str) {
     return fgets(str, 0x7fffffff, stdin);
 }

test/test_io.c

@@ -1,38 +1,17 @@
 
-#include <ctype.h>
 #include <stdio.h>
- 
-void demo_scanf(const char* fmt, FILE* s)
-{
-    while (*fmt != '\0') {
-        if (*fmt == '%') {
-            int c;
-            switch (*++fmt) {
-                case 'u':
-                    while (isspace(c=getc(s))) {}
-                    unsigned int num = 0;
-                    while (isdigit(c)) {
-                        num = num*10 + c-'0';
-                        c = getc(s);
-                    }
-                    printf("%%u scanned %u\n", num);
-                    ungetc(c, s);
-                    break;
-                case 'c':
-                    c = getc(s);
-                    printf("%%c scanned '%c'\n", c);
-                    break;
-            }
-        } else {
-            ++fmt;
-        }
-    }
-}
- 
+
 int main(void)
 {
-    printf("Please enter a string: ");
-    fflush(stdout);
-    demo_scanf("%u%c", stdin);
+    char const *filename = "todo";
+    FILE *f = fopen(filename, "rb");
+    if(f == NULL) {
+        printf("File %s doesn't exist\n", filename);
+        return 1;
+    }
+    int c;
+    while((c=fgetc(f)) != EOF) {
+        putchar(c);
+    }
     return 0;
 }

todo

@@ -2,6 +2,8 @@
 general:
 *   Start writing documentation concerning various implementation defined
     behaviours of the library.
+*   Ok I just realised that I assumed that wchar_t is a 16-bit string in
+    a bunch of places.
 
 math.h:
 *   exp
@@ -33,6 +35,14 @@ stdio.h:
     with a buffer would increase performance.
 *   Formatted scan
 *   %s precision should specify how much characters to *write*
+*   %Ls this is an actual weird territory. If (wchar_t *) is a unicode string
+    then to determine it's "width" (to figure out field padding) would require
+    to use a Unicode composition algorithm. But the problem is that windows
+    Unicode rendering advances text by 2 units, even if it's 1 graphical
+    character that was composed from 2 unicode characters. The question
+    becomes: do we implement the thing correctly by using a more complex
+    solution, or do we succumb to windows' bullshittery. I guess the answer is
+    obvious. That's why I wrote this todo item :D
 
 stdlib.h:
 *   Strtod base 16 must be correctly rounded