Q37507: PRB: "Floating-point Support Not Loaded" Error with scanf()

Article: Q37507
Product(s): Microsoft C Compiler
Version(s): winnt:
Operating System(s): 
Keyword(s): kbCRT kbVC
Last Modified: 25-JUL-2001

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The information in this article applies to:

- The C Run-Time (CRT), included with:
   - Microsoft C for MS-DOS, versions 6.0, 6.0a, 6.0ax 
   - Microsoft C for OS/2, versions 6.0, 6.0a 
   - Microsoft C/C++ for MS-DOS, version 7.0 
   - Microsoft Visual C++, versions 1.0, 1.5 
   - *EDITOR Please do not choose this product*Microsoft Visual C++ 32-bit Edition* use 241, 265, 225, versions 1.0, 2.0, 4.0 
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SYMPTOMS
========

When an application uses the scanf() function to read a floating-point value
from the console into an uninitialized "float" type global variable, an R6002
"floating-point format support not loaded" error occurs. This error also occurs
when any formatted input routine is used to read a value.

CAUSE
=====

The compiler does not generate a reference to the __fltused variable that
instructs the linker to load the floating-point support module.

RESOLUTION
==========

To work around this problem, initialize the floating-point variable or use the
variable in an expression in the routine that contains the scanf() call.

STATUS
======

This behavior is expected. To minimize the size of the executable file, the
compiler loads floating-point support only when it is required.

MORE INFORMATION
================

When a module uses only one of the formatted input routines and does not also
initialize a floating-point variable, the compiler does not load floating-point
support.

Remove the comment indication from either or both of the two lines in the sample
code below to eliminate the R6002 error.

Sample Code
-----------

     /*
      * Compile options needed: none
      */ 

     #include <stdio.h>
     float x ;

     main()
     {
     // Remove the comment from the next line to eliminate the error.
     // x = 2.3 ;

        scanf ("%f", &x) ;

     // Remove the comment from the next line to eliminate the error.
     // printf ("%f\n", x) ;
     }

Additional query words: floating point not loaded

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Keywords          : kbCRT kbVC 
Technology        : kbVCsearch kbAudDeveloper kbCRT
Version           : winnt:
Issue type        : kbprb

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