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* HACKING: Updated the part concerning const_cast, str_unconst and

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the NULL pointer in varargs.
This commit is contained in:
Roland Illig 2005-04-14 01:27:12 +00:00
parent 2229354f3d
commit d2de14cf4e
1 changed files with 12 additions and 11 deletions
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23
HACKING
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@ -161,7 +161,7 @@ Thanks to glib, the code has almost no hardcoded limits, since there are
many ways to avoid them. For example, when you want to concatenate
strings, use the g_strconcat() function:
new_text = g_strconcat (username, " ", password, NULL);
new_text = g_strconcat (username, " ", password, (char *)0);
This allocates new memory for the string, so you should use g_free() on
the result.
@ -322,14 +322,7 @@ const: For every function taking a string argument, decide whether you
"const char *". If your implementation needs to modify the string,
use g_strdup to create a local copy.
const_cast: We use many libraries that do not know about "const char *" and
thus declare their functions to require "char *". In cases where we
know the function does not modify the string, we can use the macro
const_cast(char *, string_var) instead of a simple (char *) string_var
to make the intent clear. In cases where we are not sure what the
function does with the string, we should use g_strdup to pass
dynamically allocated strings.
const_cast: Has been replaced by str_unconst.
g_free: g_free handles NULL argument too, no need for the comparison.
Bad way:
if (old_dir) g_free (old_dir);
@ -351,7 +344,7 @@ g_strlcpy: Whenever you use this function, be sure to add "glibcompat.h"
no such function.
NULL: When you pass NULL as an argument of a varargs function, cast the
NULL to the appropriate data type. If a system #defines NULL to
0 to the appropriate data type. If a system #defines NULL to
be 0 (at least NetBSD and OpenBSD do), and the sizes of int and
a pointer are different, the argument will be passed as int 0,
not as a pointer.
@ -362,7 +355,7 @@ NULL: When you pass NULL as an argument of a varargs function, cast the
rpc_get (vfs/mcfsutil.h), rpc_send (vfs/mcfsutil.h).
example:
char *path = g_strconcat("dir", "/", "file", (char *) NULL);
char *path = g_strconcat("dir", "/", "file", (char *)0);
size_t: This data type is suitable for expressing sizes of memory or the
length of strings. This type is unsigned, so you need not check
@ -370,3 +363,11 @@ size_t: This data type is suitable for expressing sizes of memory or the
strncpy: Don't use this function in newly created code. It is slow, insecure
and hard to use. A much better alternative is g_strlcpy (see there).
str_unconst: We use many libraries that do not know about "const char *"
and thus declare their functions to require "char *". If you
know for sure that an external function does not modify the
string, you can "unconst" a string using the function
str_unconst(). If you are not sure whether the function modifies
the string, you should use g_strdup() to pass a copy of a string
to the function. Don't forget to call g_free() after work is done.