Write on thermal printer device in golang
up vote
1
down vote
favorite
I have a thermal printer(ESC/POS) already configured on my linux machine and using the terminal command (as root) I can make it print:
echo "Hello!" > /dev/usb/lp0
However, doing the same procedure in golang nothing happens:
package main
import (
"fmt"
"os"
)
func main() {
fmt.Println("Hello Would!")
f, err := os.Open("/dev/usb/lp0")
if err != nil {
panic(err)
}
defer f.Close()
f.Write(byte("Hello world!"))
}
What am I doing wrong?
linux
go thermal-printer asked Nov 10 at 0:13
Augusto Pimenta
134
add a comment |
up vote
1
down vote
favorite
I have a thermal printer(ESC/POS) already configured on my linux machine and using the terminal command (as root) I can make it print:
echo "Hello!" > /dev/usb/lp0
However, doing the same procedure in golang nothing happens:
package main
import (
"fmt"
"os"
)
func main() {
fmt.Println("Hello Would!")
f, err := os.Open("/dev/usb/lp0")
if err != nil {
panic(err)
}
defer f.Close()
f.Write(byte("Hello world!"))
}
What am I doing wrong?
linux
go thermal-printer asked Nov 10 at 0:13
Augusto Pimenta
134
Maybe something like godoc.org/github.com/google/gousb?
– grooveplex
Nov 10 at 0:17
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I have a thermal printer(ESC/POS) already configured on my linux machine and using the terminal command (as root) I can make it print:
echo "Hello!" > /dev/usb/lp0
However, doing the same procedure in golang nothing happens:
package main
import (
"fmt"
"os"
)
func main() {
fmt.Println("Hello Would!")
f, err := os.Open("/dev/usb/lp0")
if err != nil {
panic(err)
}
defer f.Close()
f.Write(byte("Hello world!"))
}
What am I doing wrong?
linux
go thermal-printer asked Nov 10 at 0:13
Augusto Pimenta
134
I have a thermal printer(ESC/POS) already configured on my linux machine and using the terminal command (as root) I can make it print:
echo "Hello!" > /dev/usb/lp0
However, doing the same procedure in golang nothing happens:
package main
import (
"fmt"
"os"
)
func main() {
fmt.Println("Hello Would!")
f, err := os.Open("/dev/usb/lp0")
if err != nil {
panic(err)
}
defer f.Close()
f.Write(byte("Hello world!"))
}
What am I doing wrong?
linux
go thermal-printer linux
go thermal-printer asked Nov 10 at 0:13
Augusto Pimenta
134
asked Nov 10 at 0:13
Augusto Pimenta
134
asked Nov 10 at 0:13
Augusto Pimenta
134
asked Nov 10 at 0:13
Augusto Pimenta
134
asked Nov 10 at 0:13
Augusto Pimenta
134
134
Maybe something like godoc.org/github.com/google/gousb?
– grooveplex
Nov 10 at 0:17
add a comment |
Maybe something like godoc.org/github.com/google/gousb?
– grooveplex
Nov 10 at 0:17
Maybe something like godoc.org/github.com/google/gousb?
– grooveplex
Nov 10 at 0:17
Maybe something like godoc.org/github.com/google/gousb?
– grooveplex
Nov 10 at 0:17
add a comment |
1 Answer
1
active
oldest
votes
up vote
8
down vote
accepted
As described in the documentation os.Open() opens a file read-only.
You would have discovered the problem if you had checked the return from your Write() call. Always check errors. Don't ignore them, even in tiny programs like this; they will give you a clue as to what is wrong.
To fix the problem, open the device special for writing with os.OpenFile().
f, err := os.OpenFile("/dev/usb/lp0", os.O_RDWR, 0)
answered Nov 10 at 0:50
Michael Hampton
7,18233168
2
upvote forAlways check errors:)
– Dmitry Harnitski
Nov 10 at 0:59
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
8
down vote
accepted
As described in the documentation os.Open() opens a file read-only.
You would have discovered the problem if you had checked the return from your Write() call. Always check errors. Don't ignore them, even in tiny programs like this; they will give you a clue as to what is wrong.
To fix the problem, open the device special for writing with os.OpenFile().
f, err := os.OpenFile("/dev/usb/lp0", os.O_RDWR, 0)
answered Nov 10 at 0:50
Michael Hampton
7,18233168
2
upvote forAlways check errors:)
– Dmitry Harnitski
Nov 10 at 0:59
add a comment |
up vote
8
down vote
accepted
As described in the documentation os.Open() opens a file read-only.
You would have discovered the problem if you had checked the return from your Write() call. Always check errors. Don't ignore them, even in tiny programs like this; they will give you a clue as to what is wrong.
To fix the problem, open the device special for writing with os.OpenFile().
f, err := os.OpenFile("/dev/usb/lp0", os.O_RDWR, 0)
answered Nov 10 at 0:50
Michael Hampton
7,18233168
2
upvote forAlways check errors:)
– Dmitry Harnitski
Nov 10 at 0:59
add a comment |
up vote
8
down vote
accepted
up vote
8
down vote
accepted
As described in the documentation os.Open() opens a file read-only.
You would have discovered the problem if you had checked the return from your Write() call. Always check errors. Don't ignore them, even in tiny programs like this; they will give you a clue as to what is wrong.
To fix the problem, open the device special for writing with os.OpenFile().
f, err := os.OpenFile("/dev/usb/lp0", os.O_RDWR, 0)
answered Nov 10 at 0:50
Michael Hampton
7,18233168
As described in the documentation os.Open() opens a file read-only.
You would have discovered the problem if you had checked the return from your Write() call. Always check errors. Don't ignore them, even in tiny programs like this; they will give you a clue as to what is wrong.
To fix the problem, open the device special for writing with os.OpenFile().
f, err := os.OpenFile("/dev/usb/lp0", os.O_RDWR, 0)
answered Nov 10 at 0:50
Michael Hampton
7,18233168
answered Nov 10 at 0:50
Michael Hampton
7,18233168
answered Nov 10 at 0:50
Michael Hampton
7,18233168
answered Nov 10 at 0:50
Michael Hampton
7,18233168
7,18233168
2
upvote forAlways check errors:)
– Dmitry Harnitski
Nov 10 at 0:59
add a comment |
2
upvote forAlways check errors:)
– Dmitry Harnitski
Nov 10 at 0:59
2
2
upvote for
Always check errors :)– Dmitry Harnitski
Nov 10 at 0:59
upvote for
Always check errors :)– Dmitry Harnitski
Nov 10 at 0:59
add a comment |
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Maybe something like godoc.org/github.com/google/gousb?
– grooveplex
Nov 10 at 0:17