Procedure

   iswhsp_c ( Determine whether a string is white space ) 

   SpiceBoolean iswhsp_c ( ConstSpiceChar * string )

Abstract

   Return a boolean value indicating whether a string contains
   only white space characters.

Required_Reading

   None.

Keywords

   FILES
   TEXT

Brief_I/O

   VARIABLE  I/O  DESCRIPTION
   --------  ---  --------------------------------------------------
   string     I   String to be tested.

   The function returns the boolean value SPICETRUE if the string is
   empty or contains only white space characters; otherwise it returns
   the value SPICEFALSE.

Detailed_Input

   string      is a character pointer designating a string to be
               searched for non-white-space characters.

Detailed_Output

   The function returns the boolean value SPICETRUE if the string
   contains only white space characters; otherwise it returns the
   value SPICEFALSE.

   White space characters are those in the set

      { ' ', '\f', '\n', '\r', '\t', '\v' }

Parameters

   None.

Exceptions

   1)  If the input string pointer is null, the error SPICE(NULLPOINTER)
       is signaled.

   2)  An empty string, that is a string with a null character
       at index 0, is considered to be blank.

Files

   None.

Particulars

   This routine provides a short cut for testing lines for the presence
   of non-blank characters; this is a test which is performed frequently
   in CSPICE.

Examples

   The numerical results shown for this example may differ across
   platforms. The results depend on the SPICE kernels used as
   input, the compiler and supporting libraries, and the machine
   specific arithmetic implementation.

   1) Read a text file; print the non-blank lines.

      Use the meta-kernel shown below as example of text file to
      read.


         KPL/MK

         File name: iswhsp_ex1.tm

         This meta-kernel is intended to support operation of SPICE
         example programs.

         This file contains only free formatted text (no data)
         as it is used in the iswhsp_c example as a plain text
         file, but it could also contain data.

         ...

         End of meta-kernel


      Example code begins here.


      /.
         Program iswhsp_ex1
      ./
      #include <stdio.h>
      #include "SpiceUsr.h"

      int main()
      {
         /.
         Local parameters.
         ./
         #define MAXLEN 81

         /.
         Local variables.
         ./
         SpiceBoolean   eof;
         SpiceChar      line [MAXLEN];

         eof = SPICEFALSE;

         while ( !eof )
         {
            rdtext_c ( "iswhsp_ex1.tm", MAXLEN, line, &eof );

            if ( !iswhsp_c(line) )
            {
               printf ( "%s\n", line );
            }
         }

         return ( 0 );
      }


      When this program was executed on a Mac/Intel/cc/64-bit
      platform, the output was:


      KPL/MK
      File name: iswhsp_ex1.tm
      This meta-kernel is intended to support operation of SPICE
      example programs.
      This file contains only free formatted text (no data)
      as it is used in the iswhsp_c example as a plain text
      file, but it could also contain data.
      ...
      End of meta-kernel

Restrictions

   None.

Literature_References

   [1]  "American National Standard for Programming Languages -- C,"
        Section 7.3.1.9., p.104, American National Standards Institute,
        1990.

Author_and_Institution

   N.J. Bachman        (JPL)
   J. Diaz del Rio     (ODC Space)

Version

   -CSPICE Version 1.1.1, 10-AUG-2021 (JDR)

       Edited the -Examples section to comply with NAIF standard.
       Replaced non-existing "txtopr_c"  and "readln_c" calls by
       equivalent "rdtext_c" in the code example. Added example's
       solution and sample input text file.

   -CSPICE Version 1.1.0, 27-AUG-1999 (NJB)

       Now checks for null input string.

   -CSPICE Version 1.0.0, 24-FEB-1999 (NJB)

       Arguments passed to isspace are now cast to unsigned char to
       suppress compilation warnings on some systems.

   -CSPICE Version 1.0.0, 08-FEB-1998 (NJB)

Index_Entries

   read a non-blank line from a text file