+<H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
+ The pointer-valued routines return NULL on error. They
+ set errno according to their success:
+
+ <STRONG>E_OK</STRONG> The routine succeeded.
+
+ <STRONG>E_BAD_ARGUMENT</STRONG>
+ Routine detected an incorrect or out-of-range argu-
+ ment.
+
+ <STRONG>E_SYSTEM_ERROR</STRONG>
+ System error occurred, e.g., malloc failure.