poking around error handling in the kernel, and noticed the following ... in include/linux/err.h, we have IS_ERR() unsurprisingly defined in terms of IS_ERR_VALUE(): #define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= \ (unsigned long)-MAX_ERRNO) ... snip ... static inline bool __must_check IS_ERR(__force const void *ptr) { return IS_ERR_VALUE((unsigned long)ptr); } fair enough, and the above suggests that it's technically equivalent to use either one, but if i search under drivers/ for each: $ git grep -w IS_ERR -- drivers | wc -l 14048 $ $ git grep -w IS_ERR_VALUE -- drivers | wc -l 48 $ so IS_ERR() is pretty clearly the call of choice, and the invocations of IS_ERR_VALUE() are concentrated in a small number of files -- heck, 15 of those calls are in the single file drivers/net/ethernet/freescale/ucc_geth.c. is there any non-obvious reason for driver code to use the latter? superficially, they *seem* to be equivalent, but i've been surprised before. rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca/dokuwiki Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================