Category : C++ Source Code
Archive   : C_ALL.ZIP
Filename : TI645.ASC

PRODUCT : Borland C++ NUMBER : 645
VERSION : ALL
OS : DOS
DATE : November 4, 1992 PAGE : 1/4

TITLE : "Floating point formats not linked" messages.





This document explains why you might be getting the error
FLOATING POINT FORMATS NOT LINKED : ABNORMAL PROGRAM TERMINATION
and tells you how to resolve it. The problems and solutions
below apply to ALL versions of Turbo C, Turbo C++, and Borland
C++, except where noted.

What are floating point formats?

Floating point formats are a collection of formatting information
used to manipulate floating point numbers in certain runtime
library functions such as scanf() and atof().

When will this be fixed?

There are no current plans to fix this because it is not a bug.
The intent is to avoid linking the floating point formats (about
1K of overhead) when they are not required. The tradeoff of this
feature is that the programmer must explicitly request that the
floating point formats to be linked in for some programs which
manipulate floats in a limited and specific fashion.

How do I resolve the error message?

Since you can get the error in a number of different ways, check
the following list of potential causes to find out how to resolve
the error. These are listed in order of most common to least
common causes.

1. CAUSE: Floating point set to . Your have your
floating point option set to None when it should be set to
either Emulation or 80x87.

FIX: Set Floating Point to or <80x87>. In the
Integrated Development Environment (IDE), this is either
under Options | Compiler | Advanced Code Generation or
Options | Compiler | Code Generation | More, depending upon
which compiler you have. With the command line compiler, use
the appropriate -f switch.

2. CAUSE: Misordered libraries when executing TLINK
(Cx.LIB listed before EMU.LIB will cause the error.)














PRODUCT : Borland C++ NUMBER : 645
VERSION : ALL
OS : DOS
DATE : November 4, 1992 PAGE : 2/4

TITLE : "Floating point formats not linked" messages.




FIX: This possibility usually occurs only when you are using
the command line compiler and are explicitly calling TLINK
separately from BCC or TCC. When executing TLINK, change the
order of the libraries to

[user libs] [GRAPHICS.LIB] EMU.LIB MATHx.LIB Cx.LIB
(libraries in brackets are optional)

Note: There is a misprint in the Borland C++ Tools &
Utilities Guide on page 58 that displays the wrong order for
libraries on the TLINK command line. The ordering shown in
the manual is exactly what will cause floating point formats
not linked.

3. CAUSE: Either the compiler is overoptimizing, or the
floating point formats really do need to be linked in because
your program manipulates floats in a limited and specific
fashion. Under certain obscure conditions, the compiler will
ignore floating point usage in scanf(). (e.g., trying to
read into a float variable that is part of an array contained
in a structure.)

FIX: If you have Borland C++ 3.0 or later, read Part A. If
you have Borland C++ 2.0 or any Turbo C or Turbo C++
compiler, read Part B. This fix is the only fix that will
solve a "PRINTF : Floating point formats not linked" error
message occurring with inline assembly.

Part A (BC++ 3.0 or later):
Add the following to one source module:

extern _floatconvert;
#pragma extref _floatconvert

The README and HELPME!.DOC files that shipped with
Borland C++ 3.0 incorrectly say that only

#pragma extref _floatconvert

is required in order to resolve the FPFNL error. If you
do not include the "extern _floatconvert;" line you will
get the error "Undefined symbol _floatconvert." You will
also get the same undefined symbol if the "extern













PRODUCT : Borland C++ NUMBER : 645
VERSION : ALL
OS : DOS
DATE : November 4, 1992 PAGE : 3/4

TITLE : "Floating point formats not linked" messages.




_floatconvert" comes after the #pragma line instead of
before. Note that the #pragma line does not have a
semicolon at the end of the line. If you put a semicolon
there, you will get the error "Bad pragma directive
syntax."
The README that shipped with Borland C++ 3.1 says that

extern void _floatconvert();
#pragma extref _floatconvert

This should work, as well. It doesn't really matter
whether _floatconvert is a variable or a function; it
only matters that it is some symbol that the linker will
recognize.
The HELPME!.DOC for BC++ 3.1 has the correct two lines to
add.

Part B (BC++ 2.0 or TC or TC++):
Add the following force_fpf() function to one source
module. It is not necessary to call this function; just
include it in one of your modules.

static void force_fpf()
{
float x, *y; /* Just declares two variables */
y = &x; /* Forces linkage of FP formats */
x = *y; /* Suppress warning message about x */
}

4. CAUSE: Forgetting to put the address operator & on the scanf
variable expression. For example,
float foo;
scanf("%f", foo);

FIX: Change the code so that the & operator is used where it
is needed. For example, the above code should be
float foo;
scanf("%f", &foo);


















PRODUCT : Borland C++ NUMBER : 645
VERSION : ALL
OS : DOS
DATE : November 4, 1992 PAGE : 4/4

TITLE : "Floating point formats not linked" messages.




5. CAUSE: A bug in Turbo C 2.0 when using scanf()

FIX: Obtain and apply the patches in TC2PAT.ARC. This file
can be downloaded from the Languages / C++ / Patches section
on DLBBS (408-439-9096).

6. CAUSE: A bug in Turbo C 2.01 when using atof() or strtod()

FIX: Obtain and apply the patches in TC21PT.ARC. This file
can be downloaded from the Languages / C++ / Patches section
on DLBBS (408-439-9096).

7. CAUSE: You are trying to create a Phar Lap DOS Extender
application with the Integrated Development Environment
(IDE).

FIX: Phar Lap includes an executable called BCC286.EXE with
their DOS Extender. This program calls Borland's command-
line compiler (BCC) and command-line linker (TLINK). Since
the linker in the IDE is different than the linker at the
command line, you cannot create Phar Lap DOS Extender
applications in the IDE and expect them to run properly. If
you try to do so, you might get a floating point formats not
linked error message. The fix is to use the command line
tools, BCC and TLINK, instead of the IDE.

Keywords: FPFNL , APT

DISCLAIMER: You have the right to use this technical information
subject to the terms of the No-Nonsense License Statement that
you received with the Borland product to which this information
pertains.