Do you ever program in C? :>: -----Original Message----- :>: From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On :>: Behalf Of John Gilmore :>: Sent: Thursday, June 13, 2013 5:35 AM :>: To: IBM-MAIN@LISTSERV.UA.EDU :>: Subject: Re: DataPower XML Appliance and RACF :>: :>: About your example, it would also be my expectation that a C :>: implementation of :>: :>: int bar = (7 > 3) ; :>: :>: would set bar equal to +1, since 7 is indeed greater than 3. :>:
<snip> :>: :>: That said, and given the absence of a logical data type in C, the :>: convention of returning -1 as a surrogate for the outcome false is :>: appropriate if ugly. FSVO false but not the "logical" one meaning not true. int bar = (7<3); will always set bar to 0, never to -1. And C has had a logical type called _Bool for almost 15 years. :>: :>: It is, however, appropriate to distinguish between an outcome and a :>: return code in many, indeed most contexts, i.e., to avoid confounding :>: the true|false dichotomy with the success|fsailure dichotomy. If a C :>: function conducts a search for, say, an element of a character array :>: that has the valuew '?' and does not find one, returning -1 to :>: indicate this is in C appropriate. If instead a C function attempts :>: to open a file and does not succeed in doing so, returning -1 as an :>: indicator that it failed is not in my view enough. In this case I :>: would wish to have some further diagnostic information. The reasons why a file was not opened can be system specific. (It makes sense for Windows to report "there is no such directory" but not for z/OS when opening an MVS dataset.) So the C language standard provides a reasonably simple method than any implementation can use to report whatever condition it sees fit. In the case of opening a file, the C function returns NULL (the POSIX function returns -1) and the standard error interface "errno" can be set to a value to specify exactly what the problem was. If your system does not provide this extra information, blame whoever wrote your library function, not the language. :>: Opinions about such issues do differ; these differences are often as :>: much visceral as intellectual; and it is my guess that we shall never :>: agree about this and much else. And some are just not factual. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
