Before Tcl 8.0, the tcl_precision variable in this interpreter
controlled the conversion. As of Tcl 8.0, this argument is ignored and
17 digits of precision are always used for conversion.
double value (in)
Floating-point value to be converted.
char *dst (out)
Where to store string representing value. Must have at
least TCL_DOUBLE_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 format to generate the string, with one
special twist: the string is guaranteed to contain either
a ``.'' or an ``e'' so that it doesn't look like an integer. Where
%g would generate an integer with no decimal point, Tcl_PrintDouble
adds ``.0''.