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TCSANOW is missing from standard library #31985

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opened 2026年04月20日 12:47:02 +02:00 by Sumandora · 1 comment

Sumandora commented

2026年04月20日 12:47:02 +02:00

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Zig Version

0.15.2 (should also affect master)

Steps to Reproduce and Observed Behavior

While toying around with pseudo terminals, I realized that several constants appear to be missing in std.

There is std.c.T.CSANOW, but only for Solaris. I'm not exactly sure if this is the only one, probably not, for example, there is also TCSADRAIN, which is also only inside the Solaris struct.

I was wondering how Ghostty gets around this and turns out they just include everything using C :frown: github.com/ghostty-org/ghostty@dcc39dcd40/src/pty.zig (L177)

Expected Behavior

I don't understand Zigs working of where it puts things quite yet. I'm not sure if it's supposed to go into std.os.linux or std.posix (not sure if this is posix) or std.c, but it should definitely go somewhere, even if it just means that the linux struct in std.c.T also has the values appended, like Solaris.

You can find the values defined inside lib/libc/musl/arch/generic/bits/termios.h and a few architecture specific headers.

### Zig Version 0.15.2 (should also affect master) ### Steps to Reproduce and Observed Behavior While toying around with pseudo terminals, I realized that several constants appear to be missing in std. There is `std.c.T.CSANOW`, but only for Solaris. I'm not exactly sure if this is the only one, probably not, for example, there is also TCSADRAIN, which is also only inside the Solaris struct. --- I was wondering how Ghostty gets around this and turns out they just include everything using C :frown: https://github.com/ghostty-org/ghostty/blob/dcc39dcd401975ee77a642fa15ba7bb9f6d85b96/src/pty.zig#L177 ### Expected Behavior I don't understand Zigs working of where it puts things quite yet. I'm not sure if it's supposed to go into std.os.linux or std.posix (not sure if this is posix) or std.c, but it should definitely go somewhere, even if it just means that the linux struct in std.c.T also has the values appended, like Solaris. You can find the values defined inside `lib/libc/musl/arch/generic/bits/termios.h` and a few architecture specific headers.

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2026年04月20日 12:47:02 +02:00

linus commented

2026年04月20日 15:48:22 +02:00

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It's part of POSIX so we should probably check all OSs in std.c and see if they support it, not just Linux.

[It's part of POSIX](https://pubs.opengroup.org/onlinepubs/9799919799/functions/tcsetattr.html) so we should probably check all OSs in `std.c` and see if they support it, not just Linux. - https://github.com/torvalds/linux/blob/c1f49dea2b8f335813d3b348fd39117fb8efb428/include/uapi/asm-generic/termbits.h#L144-L147 - https://github.com/SerenityOS/serenity/blob/c11f87728421993303b0a7918788cf077a20e4f5/Kernel/API/POSIX/termios.h#L202-L205 - https://github.com/openbsd/src/blob/61290050a454c7bd1c45f7bd76b68ce255d55132/sys/sys/termios.h#L207-L209 - ...

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2026年04月20日 15:48:39 +02:00

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