Not a question, a request: Please make __attribute__((cleanup)) or the equivalent feature part of the next C standard. It's used by a lot of current software in Linux, notably systemd and glib2. It solves a major headache with C error handling elegantly. Most compilers already support it internally (since it's required by C++). It has predictable effects, and no impact on performance when not used. It cannot be imple…
My idea was to add something like the GoLang defer statement to C (as a function with some special compiler magic). The following is an example of how such a function could be used to cleanup allocated resources regardless of how a function returned:
int do_something(void) {
FILE *file1, *file2;
object_t *obj;
file1 = fopen("a_file", "w");
if (file1 == NULL) {
return -1;
}
defer(fclose, file1);
file2 = fopen("another_file", "w");
if (file2 == NULL) {
return -1;
}
defer(fclose, file2);
obj = malloc(sizeof(object_t));
if (obj == NULL) {
return -1;
}
// Operate on allocated resources
// Clean up everything
free(obj); // this could be deferred too, I suppose, for symmetry
return 0;
}