[!exec:swig] skip
[!cgo] skip

go test -v -count=1 -coverprofile=foo.p
stdout 'coverage: 100.0% of statements'

-- go.mod --
module simple

go 1.21
-- main.c --
/* A global variable */
double Foo = 3.0;

/* Compute the greatest common divisor of positive integers */
int gcd(int x, int y) {
  int g;
  g = y;
  while (x > 0) {
    g = x;
    x = y % x;
    y = g;
  }

<!-- go.dev/issue/60905, CL 559555 -->
Go 1.23 introduces a new `GOARM64` environment variable, which specifies the minimum target version of the ARM64 architecture at compile time. Allowed values are `v8.{0-9}` and `v9.{0-5}`. This may be followed by an option specifying extensions implemented by target hardware. Valid options are `,lse` and `,crypto`.

The `GOARM64` environment variable defaults to `v8.0`.

### RISC-V {#riscv}

stdout 'on'

go env
stdout 'GOTELEMETRY=''?on''?'
stdout 'GOTELEMETRYDIR=''?'$userconfig'[\\/]go[\\/]telemetry''?'
! go env -w GOTELEMETRY=off
stderr '^go: unknown go command variable GOTELEMETRY$'
! go env -w GOTELEMETRYDIR=foo

3DES cipher suites were removed from the default list used when
[Config.CipherSuites] is nil. The default can be reverted adding `tls3des=1` to

# Now override it to something writable.
env GOENV=$WORK/envdir/go/env
go env GOENV
stdout envdir[\\/]go[\\/]env

# go env shows all variables
go env
stdout GOARCH=
stdout GOOS=
stdout GOROOT=

# go env ignores invalid flag in GOFLAGS environment variable
env GOFLAGS='=true'
go env

# checking errors
! go env -w
stderr 'go: no KEY=VALUE arguments given'
! go env -u

# 'go test' should not implicitly set GOROOT in the process environment
# (because that could mask an unexpected production dependency on the GOROOT
# environment variable), but 'go generate' should (because the generator may
# reasonably expect to be able to locate the GOROOT for which it is generating
# code).

[trimpath] stop

! go run -trimpath .
stdout '^GOROOT $'

and $WORK/gopath/src/hello.go containing the listed contents.

Each line of a script is parsed into a sequence of space-separated command
words, with environment variable expansion within each word and # marking
an end-of-line comment. Additional variables named ':' and '/' are expanded
within script arguments (expanding to the value of os.PathListSeparator and
os.PathSeparator respectively) but are not inherited in subprocess environments.

go build -o mkold$GOEXE mkold.go

# Make test input files appear to be a minute old.
exec ./mkold$GOEXE 1m testcache/file.txt
exec ./mkold$GOEXE 1m testcache/script.sh

# If the test reads an environment variable, changes to that variable
# should invalidate cached test results.
env TESTKEY=x
go test testcache -run=TestLookupEnv
go test testcache -run=TestLookupEnv
stdout '\(cached\)'

# GODEBUG is always read
env GODEBUG=asdf=1

## Tools {#tools}

### Go command {#go-command}

Setting the `GOROOT_FINAL` environment variable no longer has an effect
([#62047](/issue/62047)).
Distributions that install the `go` command to a location other than
`$GOROOT/bin/go` should install a symlink instead of relocating
or copying the `go` binary.

<!-- go.dev/issue/34208, CL 563137, CL 586095 -->
The new `go` `env` `-changed` flag causes the command to print only

reduce the impact such changes have on Go developers
using newer toolchains to compile old code.

A GODEBUG setting is a `key=value` pair
that controls the execution of certain parts of a Go program.
The environment variable `GODEBUG`
can hold a comma-separated list of these settings.
For example, if a Go program is running in an environment that contains

	GODEBUG=http2client=0,http2server=0