bkr@mcshh.hanse.de (Bjoern Kriews) (07/15/90)
Hi ! I am want to let my code now whether a routine returning NULL on failure failed because of an I/O Error are for a logical mistake. For example, I'm setting a global variable = errno after a failed malloc(), then do an fclose() and return. I want to set this global to zero if the code failed because of any error not setting errno. My question is: What does the standard say about the value 0 for errno ? Can I assume that there is no errno.h defining any errorcode = 0 ? Any help appreciated, Bjoern -- bkr@mcshh.hanse.de - Bjoern Kriews / Stormsweg 6 / 2000 Hamburg 76 / W-Germany
gwyn@smoke.BRL.MIL (Doug Gwyn) (07/16/90)
In article <7798@mcshh.hanse.de> bkr@mcshh.hanse.de (Bjoern Kriews) writes:
-I am want to let my code now whether a routine returning NULL on failure
-failed because of an I/O Error are for a logical mistake. For example,
-I'm setting a global variable = errno after a failed malloc(), then do
-an fclose() and return. I want to set this global to zero if the code
-failed because of any error not setting errno.
-What does the standard say about the value 0 for errno ?
-Can I assume that there is no errno.h defining any errorcode = 0 ?
As I understand your question, the answer is that all error numbers that
may be set by standard library functions are positive integers. Therefore
you may safely assume that a code of 0 is different from any error code.