Provided by: tcl8.6-doc_8.6.9+dfsg-2_all bug

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 controlled 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_DOUBLE_SPACE characters of storage.
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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 format to generate the string, with one
       special twist: the string is guaranteed 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