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From: greywolf@unisoft.UUCP (The Grey Wolf)
Newsgroups: comp.lang.c
Subject: Re: Possible scanf bug?
Message-ID: <3343@unisoft.UUCP>
Date: 5 Feb 91 21:32:57 GMT
References: <16134@sdcc6.ucsd.edu> <146@thor.UUCP> <RJOHNSON.91Jan31110927@olorin.shell.com>
Reply-To: greywolf@unisoft.UUCP (The Grey Wolf)
Organization: Foo Bar and Grill
Lines: 37

In article <RJOHNSON.91Jan31110927@olorin.shell.com> rjohnson@shell.com (Roy Johnson) writes:
>In article <146@thor.UUCP> scjones@thor.UUCP (Larry Jones) writes:
	[ scanf not reading what the user wants, said to return zero ]
>Except that it would return 1, for number of variables assigned, not
>number of formats read.

From BSD 4.3 UNIX, scanf(3S) manual page:

    "The _s_c_a_n_f functions return the number of successfully
     matched and assigned input items[*].  This can be used to decide how many
     ^^^^^^^^^^^^^^^^^^^^ [implies both]
     input items were found.  The constant EOF is returned upon end of input;
     note that this is different from 0, which means that no conversion was
     done; if conversion was intended, it was frustrated by an inappropriate
     character in the input."

The Pyramid OSx (BSD) man page reads likewise.

[*] The SunOS 3.5 and 4.0.3 manuals and the Pyramid OSx (AT&T) man page read
similarly, but with the stipulation inserted here:
    "...this number can be zero in the event of an early conflict between
     an input character and the control string.
>
>--
>======= !{sun,psuvax1,bcm,rice,decwrl,cs.utexas.edu}!shell!rjohnson =======
>"If he exploded, all of Manhattan would be talking in high, squeaky voices
>for months!"  "Cool." -- When I Was Short
>Roy Johnson, Shell Development Company

Of course, how it actually works in *practice* may vary from system to
system (depending upon how braindead your implementation of the stdio
functions is).
-- 
thought:  I ain't so damb dumn!	| Your brand new kernel just dump core on you
war: Invalid argument		| And fsck can't find root inode 2
				| Don't worry -- be happy...
...!{ucbvax,acad,uunet,amdahl,pyramid}!unisoft!greywolf