Tcl_PrintDouble(3) Tcl Library Procedures Tcl_PrintDouble(3)

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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

Tcl 8.0 Tcl_PrintDouble(3)