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From: phil@adam.adelaide.edu.au (Phil Kernick)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: SAS-C problem (bug) with fscanf
Message-ID: <phil.669865837@adam.adelaide.edu.au>
Date: 25 Mar 91 01:50:37 GMT
References: <FIFFI.91Mar24165431@pc3.cs.tu-berlin.de>
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fiffi@opal.cs.tu-berlin.de (Carsten Hoehne) writes:

>fscanf has the following template
>fsanf(File *file,char *format-string,...)

[stuff deleted]

>3. fscanf(file,"\n%c",&c) must skip white spaces and then read a non blank
>                          character in the Variable c

This is not how scanf works with characters.  From the unix man pages...

     The control string usually  contains  conversion  specifica-
     tions,  which  are  used  to  direct interpretation of input
     sequences.  The control string may contain:

          1. White-space  characters  (SPACE,  TAB,  or  NEWLINE)
             which,  except  in  two cases described below, cause
             input to be read  up  to  the  next  non-white-space
             character.

     The conversion character indicates the interpretation of the
     input field; the corresponding pointer argument must usually
     be of a restricted type.  For a suppressed field, no pointer
     argument  is given.  The following conversion characters are
     legal:

          c    A character is expected; the  corresponding  argu-
               ment  should  be  a character pointer.  The normal
               skip over white space is suppressed in this  case;
               to read the next non-space character, use %1s.  If
               a field width is given, the corresponding argument
               should  refer  to a character array, and the indi-
               cated number of characters is read.


Notice that the "skip-whitespace" is not done with character arguments.
As the man page says, you must use %1s to get a single character after
the next whitespace, but remember, scanf with return a null terminated
string, so you will have to declare an array of char of length 2.  The
first to get your character and the second to take the \0.

Example:

        char c[2];
        fscanf(file, "%1s", c);

will do what you want.


Phil.

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