Tcl_PrintDouble(3tcl) Tcl Library Procedures Tcl_PrintDouble(3tcl)
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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 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.
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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 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
Tcl 8.0 Tcl_PrintDouble(3tcl)
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