In the smippet herunder, are strings copied or passed by address (they seem copied, but maybe only the addresses are copied) ?

[Serge Hulne]

```

package main

import (

    "fmt"

)

func f(s *string) {

    a := "Hello"

    b := "Hello"

    c := "bye"

    d := a

    fmt.Printf("pa: %p\n", &a)

    fmt.Printf("pb: %b\n", &b)

    fmt.Printf("pc: %v\n", &c)

    fmt.Printf("pd: %v\n", &d)

    fmt.Printf("p(f(u)): %p\n", s)

}

func main() {

    u := "test"

    fmt.Printf("pu: %p\n", &u)

    f(&u)

}

```

[Jan Mercl]

Please post code as just text. Also, inverted color schemes are hard to read for some people.

Wrt string copying, see https://research.swtch.com/godata

to;dr Copying a string copies two machine words.

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[Brian Candler]

In Go, everything is passed by value: that is, assignments and function calls make a copy of the value.

However, some types are effectively structs which contain pointers embedded within them.  Strings, slices, maps, channels and interface values fall into this category.

string is roughly equivalent to:

struct {

    ptr *byte  // immutable

    len int

}

[]byte is roughly equivalent to:

struct {

    buf *byte

    len int

    cap int

}

When you assign one of these values, or pass it as a parameter to a function, then the struct is copied by value - e.g. if the struct is 16 bytes then you're copying 16 bytes - but both copies contain a pointer to the same underlying data (which could be larger or smaller).

[Serge Hulne]

Thank you!