The pixel information obtained by `TIOCGWINSZ` is incorrect.

[mikoto2000]

Windows Version

Microsoft Windows [Version 10.0.22631.4317]

WSL Version

2.3.24.0

Are you using WSL 1 or WSL 2?

• [x] WSL 2
• [ ] WSL 1

Kernel Version

5.15.153.1-microsoft-standard-WSL2

Distro Version

Ubuntu 24.04

Other Software

My C application

termsize.c:

#include <fcntl.h>
#include <termios.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/ioctl.h>

void main() {
  struct winsize ws;
  int fd = open("/dev/tty", O_RDONLY);
  if(fd == -1) {
    fprintf(stderr, "Can't open tty");
    return;
  }
  int ret = ioctl(fd, TIOCGWINSZ, &ws);
  close(fd);
  fprintf(stderr, "cols %d rows %d, xpixel %d, ypixel %d.\n", ws.ws_col, ws.ws_row, ws.ws_xpixel, ws.ws_ypixel);
}

Repro Steps

1. Run gcc termsize.c -o termsize && ./termsize
2. Output stderr cols 163 rows 60, xpixel 0, ypixel 0. † xpixel and ypixel is fixed value zero.

Expected Behavior

Output xpixel and ypixel is correct value.

Actual Behavior

Output xpixel and ypixel is fixed value zero.

Diagnostic Logs

strace output:

mikoto@mnmain:~/project/tmp$ strace -ff ./termsize
execve("./termsize", ["./termsize"], 0x7fffe8f162b8 /* 28 vars */) = 0
brk(NULL)                               = 0x5637986a2000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb22957b000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=40731, ...}) = 0
mmap(NULL, 40731, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fb229571000
close(3)                                = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\220\243\2\0\0\0\0\0"..., 832) = 832
pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784, 64) = 784
fstat(3, {st_mode=S_IFREG|0755, st_size=2125328, ...}) = 0
pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784, 64) = 784
mmap(NULL, 2170256, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb22935f000
mmap(0x7fb229387000, 1605632, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x28000) = 0x7fb229387000
mmap(0x7fb22950f000, 323584, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1b0000) = 0x7fb22950f000
mmap(0x7fb22955e000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1fe000) = 0x7fb22955e000
mmap(0x7fb229564000, 52624, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fb229564000
close(3)                                = 0
mmap(NULL, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb22935c000
arch_prctl(ARCH_SET_FS, 0x7fb22935c740) = 0
set_tid_address(0x7fb22935ca10)         = 1513339
set_robust_list(0x7fb22935ca20, 24)     = 0
rseq(0x7fb22935d060, 0x20, 0, 0x53053053) = 0
mprotect(0x7fb22955e000, 16384, PROT_READ) = 0
mprotect(0x563797e1e000, 4096, PROT_READ) = 0
mprotect(0x7fb2295b3000, 8192, PROT_READ) = 0
prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0
munmap(0x7fb229571000, 40731)           = 0
openat(AT_FDCWD, "/dev/tty", O_RDONLY)  = 3
ioctl(3, TIOCGWINSZ, {ws_row=60, ws_col=163, ws_xpixel=0, ws_ypixel=0}) = 0
close(3)                                = 0
write(2, "cols 163 rows 60, xpixel 0, ypix"..., 38cols 163 rows 60, xpixel 0, ypixel 0.
) = 38
exit_group(0)                           = ?
+++ exited with 0 +++

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View similar issues

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Closed similar issues:

• TIOCGWINSZ returns wrong data when wsl called without console or with stdout/stderr redirected (#10701), similarity score: 0.78

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[mikoto2000]

I uploaded WslLogs.

WslLogs-2024-11-13_21-48-45.zip

[github-actions[bot]]

Diagnostic information

``` Detected appx version: 2.3.24.0 ```

[zcobol]

@mikoto2000 what terminal are you using?

xterm output:

zcobol@texas:~/pixel$ ./termsize
cols 80 rows 24, xpixel 804, ypixel 460.

windows terminal output;

zcobol@texas:~/pixel$ ./termsize
cols 120 rows 30, xpixel 0, ypixel 0.

[mikoto2000]

I try windows terminal preview, mintty, wsltty and wezterm.

On these terminals, getting the pixel size using printf "\x1b[14t" was successful, but getting the pixel size using TIOCGWINSZ returned 0.

[zcobol]

You might want to address this issue with the Windows Terminal guys at https://github.com/microsoft/terminal. Using termsize overs SSH on a remote Fedora server it seems to work also:

zcobol@toto:~$ ./termsize
cols 120 rows 30, xpixel 640, ypixel 480.
zcobol@toto:~$ echo $TERM
xterm-256color