Thread: fgets only returns 3 characters

I don't understand your objection, but here's how I would do it (condensed with comments). Only the first file would be distributed as plain text.

Okay, I understand your idea now. Yes, assuming that you carefully avoid redefinition errors, that will work, but of course when your project gets large enough, you will get insanely long compile times despite making a small change (and this is one criticism of the use of C++ templates without import). What's the point of avoiding linking separate object files?

Doesn't the compiler stop at a function's redefinition?

Yes, hence if you are not careful, it obviously won't work

But that would prolong the compilation delay even more.

I suppose so, but then you probably would check before adding a new struct and such.

That said, squeezing out performance is a valid reason for not linking separate object files. SQLite's amalgamation takes that approach, with "performance improvements of between 5 and 10%" claimed. Note, however, that development proceeds normally with the header + source file approach, but the amalgamation is generated at build time via a makefile.

Originally Posted by laserlight

Yes, hence if you are not careful, it obviously won't work

But that's the same as any compile-time error, right?

I'm modifying arpsmack's code, and pointer arithmetic doesn't want to work:

Code:

main.c:44: warning: assignment makes pointer from integer without a cast

(I use a reference to the char array's first index because the whole thing, when printed in GDB, displays as the actual string plus 1000-odd characters.) Because of that warning's cause, the whole while-loop busts.

EDIT: Duh. I don't need the pointer arithmetic because I'm not finding the index of the character in the string like the example I went off of. Sorry!

EDIT2: Now I wonder why puts isn't printing anything?

This is line 44.

Code:

            line = line_create(&buf[0]);

There is no function "line_create" in line.h - I didn't download the other 4 files, I expect it to be in line.h.

With no prototype, the compiler will "guess" that your function returns an integer, and line is not an integer but a pointer, so you get a warning for converting an integer to a pointer.

--
Mats

I picked a file at random -- tree.c -- and here are some of my comments about it.

Code:

#define eprintf(fmt, ...) fprintf(stderr, "%s() : line %d : " fmt, __func__, __LINE__, ##__VA_ARGS__)

__func__ and __VA_ARGS__ are C99 only, so if you're hoping for C89 compatibility you might want to use something like this.

Code:

#if defined(__STDC_VERSION) && __STDC_VERSION__ >= 199901L
    #define eprintf(fmt, ...) fprintf(stderr, "%s() : line %d : " fmt, __func__, __LINE__, ##__VA_ARGS__)
#else  /* not C99 */
    #define eprintf(fmt, ...) fprintf(stderr, "unknown : line %d : error\n", __LINE__)
#endif

Note: I'd suggest using __FILE__ as well, it can be very useful. main.c:23 tells you all you need to know, after all.

Code:

TreeNode *tree_add(Tree *this, void *value, TreeNode *before){

"this" is a C++ keyword. You might want to avoid using identifiers of that name.

Code:

Tree *tree(int (*compare)(void *, void *)){

I don't know about you, but I like using typedefs when I pass function pointers to functions.

Now from line.c:

Code:

this->text = malloc(length * sizeof(char));

sizeof(char) is always, always 1, so you can leave it out of that expression if you like.

Code:

char copy[length];

Variable-length arrays are C99 too . . .

Code:

Line *line_create(const char const *string){

Repeating const does nothing useful. I suspect you wanted

Code:

Line *line_create(const char *const string){

It does do something different if it's on the other side of the asterisk.

Oh, and &copy[0] is the same as copy.

It does do something different if it's on the other side of the asterisk.

which prevent walking the string using the passed pointer - it has no much meaning and just causes inconvinience in the function body

Originally Posted by Jesdisciple

How would __FILE__ complete the notice that a file couldn't be read? Doesn't it hold the address of the file being executed?

No, you misunderstood, __FILE__ gets replaced by the name of your source file at compile time. So if you print it out when you have an error, you know exactly which file the error happened. Together with __LINE__ can be very useful in tracking down where an error occurred. Of course, unique error messages will do the same for you...

QuantumPete

Isn't this justification equal to that for using the first const?

changing data pointed by the pointer passed to the function will affect the calling function
so the first const gives the calling function info about possible state of the data passed by pointer

changing pointer inside the called function will not affect pointer in the calling function, so the second const makes nothing for the calling function and only adds meaningless restrictions to the code of the called funtion

it is just as if you write
int myfunc(const int x);

what good it makes?

OK, so it's not equal. But if I don't plan on modifying the value, and then I accidentally do so, the second const reminds me that I'm not supposed to be doing that. If I need to modify the value that bad, I can remove the const.