[zeromq-dev] CZMQ: Error checking of z*_new() calls in other z*_new() functions

Goswin von Brederlow goswin-v-b at web.de
Thu Sep 4 11:37:06 CEST 2014


while playing with the zlist API I had to go through many source files
adjusting things here and there. One thing I noticed is that various
z*_new() functions don't check for errors on other z*_new() calls they
make (or any call that might fail). For example:

zdir_t *
zdir_new (const char *path, const char *parent)
    zdir_t *self = (zdir_t *) zmalloc (sizeof (zdir_t));
    if (parent) {
        self->path = (char *) malloc (strlen (path) + strlen (parent) + 2);
        sprintf (self->path, "%s/%s", parent, path);
        self->path = strdup (path);
    self->files = zlist_new ();
    self->subdirs = zlist_new ();

The malloc can fail, the strdup can fail, zlist_new can fail. None of
those are checked or asserted.

Is that check missing there or was it left out purposefully, letting
the code crash & burn later when allocations fail?

Other classes do check though. For example:

zhash_t *
zhash_new (void)
    zhash_t *self = (zhash_t *) zmalloc (sizeof (zhash_t));
    if (self) {
        self->prime_index = INITIAL_PRIME;
        self->chain_limit = INITIAL_CHAIN;
        size_t limit = primes [self->prime_index];
        self->items = (item_t **) zmalloc (sizeof (item_t *) * limit);
        if (!self->items)
            zhash_destroy (&self);
    return self;

Here the function will return NULL if self->items couldn't be allocated.
Imho every class should do that.


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