Grisu: trailing zero with fixed, precision=0, and showpoint

[planet36]

When printing in fixed notation with precision=0 and showpoint , there is a trailing zero when Grisu is enabled.

Using g++ 9.2.1 and libfmt master branch (9108b25)

The following code illustrates this

#include <fmt/format.h>
#include <iostream>

int main()
{
	std::cout << "FMT_VERSION=" << FMT_VERSION << '\n';
	std::cout << "FMT_GCC_VERSION=" << FMT_GCC_VERSION << '\n';
#ifdef FMT_USE_GRISU
	std::cout << "FMT_USE_GRISU=" << FMT_USE_GRISU << '\n';
#else
	std::cout << "FMT_USE_GRISU not defined\n";
#endif

	double x = 123.0;
	int precision = 0;

	std::cout.precision(precision);

	std::cout << "cout: " << std::showpoint << std::fixed << x << '\n';
	std::cout << "fmt:  " << fmt::format("{:#.{}f}", x, precision) << '\n';

	return 0;
}

Outputs:

FMT_VERSION=60001
FMT_GCC_VERSION=902
FMT_USE_GRISU=1
cout: 123.
fmt:  123.0

[vitaut]

Good catch, thanks! Fixed in 28d7191.

[planet36]

On a related note...
Running the same example code, but with Grisu disabled, I noticed a change in output introduced in commit ded1e76.

FMT_VERSION=60001
FMT_GCC_VERSION=902
FMT_USE_GRISU=0
cout: 123.
fmt: 123.000000

Using the prior commit (c7edd8e) outputs:

FMT_VERSION=60001
FMT_GCC_VERSION=902
FMT_USE_GRISU=0
cout: 123.
fmt: 123.

[vitaut]

FP formatting was being refactored =). Should be fixed now.

[planet36]

On another related note, when printing scientific notation, there is a missing decimal point.

	std::cout << "cout: " << std::showpoint << std::scientific << x << '\n';
	std::cout << "fmt:  " << fmt::format("{:#.{}e}", x, precision) << '\n';

Outputs

cout: 1.e+02
fmt: 1e+02