v crash on OpenBSD with code sent from stdin

[lcheylus]

Describe the bug

On OpenBSD/amd64, when trying to run V code sent via stdin, v compilation fails with panic.

Reproduction Steps

• Build V from sources on OpenBSD/amd64 via gmake rebuild (GNU make)
• Try to run a simple V code sent from stdin: echo "println(2+5)" | ./v run -

Expected Behavior

No error when running V code sent from stdin => V code compiles and runs as expected.

OK on Linux Debian/amd64

$ echo "println(2+5)" | ./v run -
7

Current Behavior

Crash/Panic on OpenBSD/amd64:

$ echo "println(2+5)" | ./v run -
V panic: tos(): nil string
 v hash: 0e4ae76
    pid: 0x10fe9
    tid: 0x2f263da70
/tmp/v_1000/v.01KF0H62NX48N498NN007C258H.tmp.c:22255: at builtin___v_panic: Backtrace
/tmp/v_1000/v.01KF0H62NX48N498NN007C258H.tmp.c:22562: by builtin__tos
/tmp/v_1000/v.01KF0H62NX48N498NN007C258H.tmp.c:27218: by os__get_raw_line
/tmp/v_1000/v.01KF0H62NX48N498NN007C258H.tmp.c:27777: by os__get_raw_lines
/tmp/v_1000/v.01KF0H62NX48N498NN007C258H.tmp.c:27786: by os__get_raw_lines_joined
/tmp/v_1000/v.01KF0H62NX48N498NN007C258H.tmp.c:32116: by v__pref__parse_args_and_show_errors
/tmp/v_1000/v.01KF0H62NX48N498NN007C258H.tmp.c:63204: by main__main
/tmp/v_1000/v.01KF0H62NX48N498NN007C258H.tmp.c:64280: by main

Possible Solution

No response

Additional Information/Context

No response

V version

V 0.5.0 0e4ae76

Environment details (OS name and version, etc.)

V full version	V 0.5.0 0e4ae76
OS	openbsd, 7.8, GENERIC.MP#192
Processor	4 cpus, 64bit, little endian
Memory	1.41GB/3.98GB
V executable	/home/fox/dev/vlang.git/v
V last modified time	2026-01-15 09:53:33
V home dir	OK, value: /home/fox/dev/vlang.git
VMODULES	OK, value: /home/fox/.vmodules
VTMP	OK, value: /tmp/v_1000
Current working dir	OK, value: /home/fox/dev/vlang.git
Git version	git version 2.52.0
V git status	weekly.2026.03-20-g0e4ae765
.git/config present	true
cc version	OpenBSD clang version 19.1.7
gcc version	egcc (GCC) 11.2.0
clang version	OpenBSD clang version 19.1.7
tcc version	tcc version 0.9.28rc 2025-05-27 HEAD@cb39bc4c (x86_64 OpenBSD)
tcc git status	thirdparty-openbsd-amd64 200e7752
emcc version	N/A
glibc version	N/A

[lcheylus]

After debug/tests, this issue comes from a bug on OpenBSD with get_raw_line function (from vlib/v/os.c.v) used to read/parse V code sent from stdin.

On OpenBSD, when reading inputs with C.getline, at the end of file, the variable/pointer buf = 0 => panic when calling tos function (from vlib/builtin/string.v).
On Linux, buf pointer != 0 for EOF after call of C.getline => no panic when calling tos function.

I have a fix on OpenBSD for this issue ; will post a PR ASAP.