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man pages section 3: Extended Library Functions, Volume 1

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Updated: Wednesday, July 27, 2022
 
 

Tcl_PrintDouble (3tcl)

Name

Tcl_PrintDouble - Convert floating value to string

Synopsis

#include <tcl.h>

Tcl_PrintDouble(interp, value, dst)

Description

Tcl_PrintDouble(3tcl)       Tcl Library Procedures       Tcl_PrintDouble(3tcl)



______________________________________________________________________________

NAME
       Tcl_PrintDouble - Convert floating value to string

SYNOPSIS
       #include <tcl.h>

       Tcl_PrintDouble(interp, value, dst)

ARGUMENTS
       Tcl_Interp *interp (in)          Before   Tcl  8.0,  the  tcl_precision
                                        variable  in  this  interpreter   con-
                                        trolled  the  conversion.   As  of Tcl
                                        8.0, this argument is ignored and  the
                                        conversion   is   controlled   by  the
                                        tcl_precision  variable  that  is  now
                                        shared by all interpreters.

       double value (in)                Floating-point value to be converted.

       char *dst (out)                  Where to store the string representing
                                        value.  Must have  at  least  TCL_DOU-
                                        BLE_SPACE characters of storage.
______________________________________________________________________________

DESCRIPTION
       Tcl_PrintDouble  generates  a string that represents the value of value
       and stores it in memory at the location given by dst.  It uses %g  for-
       mat to generate the string, with one special twist: the string is guar-
       anteed to contain either a "."  or an "e" so that it does not look like
       an  integer.  Where %g would generate an integer with no decimal point,
       Tcl_PrintDouble adds ".0".

       If the tcl_precision value is non-zero, the result will have  precisely
       that  many digits of significance.  If the value is zero (the default),
       the result will have the fewest digits needed to represent  the  number
       in  such a way that Tcl_NewDoubleObj will generate the same number when
       presented with the given string.  IEEE semantics of  rounding  to  even
       apply to the conversion.

KEYWORDS
       conversion, double-precision, floating-point, string



ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+------------------+
       |ATTRIBUTE TYPE | ATTRIBUTE VALUE  |
       +---------------+------------------+
       |Availability   | runtime/tcl-8    |
       +---------------+------------------+
       |Stability      | Uncommitted      |
       +---------------+------------------+

NOTES
       Source  code  for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-
       code-downloads.html.

       This     software     was    built    from    source    available    at
       https://github.com/oracle/solaris-userland.   The  original   community
       source was downloaded from  http://prdownloads.sourceforge.net/tcl/tcl-
       core8.6.7-src.tar.gz.

       Further information about this software can be found on the open source
       community website at https://www.tcl.tk/.



Tcl                                   8.0                Tcl_PrintDouble(3tcl)