Path: utzoo!dptcdc!jarvis.csri.toronto.edu!mailrus!uflorida!gatech!ncsuvx!ece-csc!ncrcae!hubcap!disd
From: disd@hubcap.clemson.edu (BJ Backitis)
Newsgroups: comp.sys.amiga
Subject: Manx and floats
Message-ID: <5135@hubcap.clemson.edu>
Date: 17 Apr 89 16:11:46 GMT
Distribution: na
Organization: Clemson University, Clemson, SC
Lines: 60

I don't think this qualifies for .tech.  It's probably just a
misapprehension of either the Manx docs or the C language (or both).

Yesterday, for the first time, I decided to use floating point numbers
with the Manx compiler.  (I know, "Ick! You *want* to use floats?")
Never mind why, I just do.  Anyway  I read in the documentation that in
order to use floats, one must compile using the +f option.  +ff for FFP,
and +fi for IEEE.  Then you must link using the appropriate math
library.  (Though it isn't clear which libraries are appropriate for
which options.)  Well the docs make mention of an mx.lib.  Mx.lib
doesn't exist in my LIB directory.  The on-disk release notes say that
the mx.lib's were removed for rel 3.6a, but they don't say what is
intended to replace them.

Anyway, to my problem.  I have need to convert text of the following
sort, " 2.78 \n", to the corresponding floating point value.  "Okay", says
I, "I'll just use sscanf."  Right.  So I added something similar to the
following to my code:

char text[80];
float number;

/* We do an fgets to get the digits from a file and put them to 'text'
*/

/* Why *does* fgets return the string *plus* the newline character? */ 

/* then .... */

sscanf(text,"%f",&number);

I compiled the program using either one of the +f flags and linked using
the following:

ln -g [.o files here] -larp -l["appropriate" math lib here] -lc

Now according to SDB, text is indeed " 2.78 \n", but number does not get
converted to the floating point equivalent.  I played around with sscanf
a little using an integer variable just to see if sscanf would work with
ints.  (SDB makes for a wonderful C interpreter. :-)  It converted text
to 2 and stored it in the int variable just so.  So sscanf works as
advertised, but something needed for proper float use is missing.

Does anyone have any suggestions?  ("Buy Lattice 5.02." or "Wait for
Manx 5.0" are not acceptable suggestions. :-)  Am I using proper
procedure?  What exactly are the correct math libraries for floats?  Am
I accidentally getting a sscanf from the arp.lib?  And will Justine
divorce Brad?

Thanks,
Gary  (seasoned Amigan, seasoned programmer, apprentice C programmer)




-- 
Frank J. ("BJ") Backitis,Jr. -- Information Systems Development
(aka KB4VSW)                    Clemson University, Clemson, SC
   
Question authority ... but make sure to raise your hand first.