#2560 (Windows v5.4.5) Plotting binary data from stdin does not work.

[Takashi Yano]

Environment

• Version: gnuplot 5.4.5 (Windows binary), and 5.5.0-test
• OS: Windows 10 (22H2) 64-bit

Overview

Plotting binary data read from stdin does not work in gnuplot 5.4.5. Git master [89a9ddc8964a80b42270dd66990c8c0f635f138d] (5.5.0) does not have this problem (works correctly).

How to reproduce the issue

1) Save the following text into file 'test-gnuplot.c'.

#include <stdio.h>

int main()
{
        const int n = 11;
        float x, y;
        printf("set term windows\n");
        printf("plot \"-\" binary record=%d w linesp\n", n);
        for (int i=0; i<n; i++) {
                x = i; y = x*x;
                fwrite(&x, sizeof(float), 1, stdout);
                fwrite(&y, sizeof(float), 1, stdout);
        }
        fflush(stdout);
        getchar();
        return 0;
}

2) Compile 'test-gnuplot.c' with gcc test-gnuplot.c -o test-gnuplot.
3) Run ./test-gnuplot | gnuplot.
4) The graph does not appear with gnuplot 5.4.5.

[Tatsuro MATSUOKA]

I have tested on 5.4.x binaries.
The graph appears with 5.4.1, and 5.4.2 .
The graph does not appear with 5.4.3, 5.4.4, and 5.4.5 .

[Tatsuro MATSUOKA]

I cloned the latest stable branch source.
git clone -b branch-5-4-stable git://git.code.sf.net/p/gnuplot/gnuplot-main

git log

commit 7e85bfde2bcfafa09cfb19a6d1603d0b0253f17f (HEAD -> branch-5-4-stable, origin/branch-5-4-stable)
Author: Bastian Maerkisch <bmaerkisch@web.de>
Date:   Tue Feb 15 22:44:33 2022 +0100

The graph appears using the above.

[Takashi Yano]

Thanks! I also can confirm that the issue is already fixed in branch-5-4-stable (5.4.6 alpha). So, we can expect the issue will most likely not occur in the next release.

[Takashi Yano]

Oh, v5.4.5 was not applied the following commit yet.

commit 780f8bd414e67c6a226efa7952e134d732feb283
Author: Takashi Yano <tyan0@users.sourceforge.net>
Date:   Tue Feb 15 22:44:15 2022 +0100

    windows console: buffered pipe input

    Use read() instead of fgetc() to improve read speed. Avoid mixed access to
    pipe by our pipe reading thread and C file functions to prevent race condition.

    Bug #2491

    (cherry picked from commit c128262f2f57aa53174d3bb7b672aff6ee3a9b79)

I see.