Hi Jusitn,
I realised I have value_len field in my arguments.I did this :
func Nitish(key *C.char, value *C.char, value_len C.size_t){
f.WriteString(C.GoString(key)+ ":")
s := C.GoStringN(value, C.int(value_len))
//fmt.Println(s)
f.WriteString(s)
f.WriteString("\n")
}
Am I doing it correctly?
Thanks
On Wed, May 1, 2019 at 4:40 PM Nitish Saboo <nitish.sabo...@gmail.com>
wrote:
> Hi Justin,
>
> As you had suggested:
> ****************************************
> You could use something like this:
> https://play.golang.org/p/fcE2UJEUFPy
>
> That example has the option of only converting a fixed number of bytes
> from the C string to the Go string, if you know how big the prefix is.
> *************************************************
>
>
> I made the following changes to my function:
>
> func Nitish(key *C.char, value *C.char, value_len C.size_t){
>
> f.WriteString(C.GoString(key)+ ":")
> value1 := C.CString(C.GoString(value))
> value_len1 := C.size_t(value1)
> // If we know the max size of characters
> // that we are looking for, then we can
> // limit how many we need to convert from
> // the C string
> const maxLen = 40
> if value_len1 > maxLen {
> value_len1 = C.size_t(maxLen)
> }
>
> s := C.GoStringN(value, C.int(value_len1))
> //fmt.Println(s)
>
> parts := strings.SplitN(s, " ", 2)
> //fmt.Println(parts[0])
> f.WriteString(parts[0])
> f.WriteString("\n")
>
> }
>
> *value *field is pointer to strings in C.I am getting the following error:
>
> # command-line-arguments
> ./main.go:109:24: cannot convert value1 (type *_Ctype_char) to type
> _Ctype_ulong
> makefile:6: recipe for target 'main' failed
> make: *** [main] Error 2
>
> I am new to cgo.I know I am making a silly mistake to fetch the value of
> value1.Can you please point it out ?
>
> Thanks,
> Nitish
>
> On Wed, May 1, 2019 at 3:10 PM Nitish Saboo <nitish.sabo...@gmail.com>
> wrote:
>
>> Actually, this is what is happening:
>>
>> func Nitish(key *C.char, value *C.char, value_len C.size_t){
>>
>> f.WriteString(C.GoString(key)+ ":")
>> f.WriteString(C.GoString(value))
>> f.WriteString("\n")
>>
>> }
>>
>> This callback method is getting called from C code multiple times.
>>
>> I am planning to write the key, value pairs in a file.But the 'value' field
>> is getting appended with the previous value in the buffer.
>>
>> These are the contents that are getting written to the file.Please see the
>> following from bottom to top.If you see for every key field (bottom to top),
>> image/gif and then 'Fp5PpR2roT6uPnte47' is getting appended as I continue
>> writing key-values to the file.
>>
>> But I need only the first word from the value field.
>>
>> Actual:
>>
>> sentfileid: - Fp5PpR2roT6uPnte47 image/gif
>> sentmimetype: Fp5PpR2roT6uPnte47 image/gif
>> rcvdfileid: image/gif
>>
>> Expected:
>>
>> sentfileid: -
>> sentmimetype: Fp5PpR2roT6uPnte47
>> rcvdfileid: image/gif
>>
>> Please let me know how can I achieve this ?
>>
>> Thanks
>>
>>
>>
>> On Wed, May 1, 2019 at 11:25 AM Nitish Saboo <nitish.sabo...@gmail.com>
>> wrote:
>>
>>> Hi,
>>> I have this method:
>>>
>>> func CallBack(key *C.char, value *C.char, value_len C.size_t){
>>>
>>> }
>>>
>>> and the *value* parameter in the arguments is containing the given
>>> string 'Fp5PpR2roT6uPnte47 image/gif'.
>>> I want to extract only first word from the string.Let me know how can I
>>> do this.
>>>
>>> I don't want to split the string into a slice of individual characters.
>>>
>>> Thanks
>>>
>>> On Wed, May 1, 2019 at 6:27 AM Justin Israel <justinisr...@gmail.com>
>>> wrote:
>>>
>>>>
>>>>
>>>> On Wednesday, May 1, 2019 at 7:06:47 AM UTC+12, Nitish Saboo wrote:
>>>>>
>>>>> Apologies.I did this 'strings.Split(C.GoString(*C.char),"").
>>>>> I am getting 'Incompatible types' compilation error.
>>>>>
>>>>
>>>> Are you literally doing this?
>>>> strings.Split(C.GoString(*C.char),"")
>>>>
>>>> Something like this should be working correctly:
>>>>
>>>> someCArr := getSomeCArr()
>>>> chars := strings.Split(C.GoString(someCArr),"")
>>>>
>>>> Is your goal to split the string into a slice of individual characters?
>>>> Because that is what your delim suggests.
>>>>
>>>>
>>>>> Thanks
>>>>>
>>>>>
>>>>> On Wed, May 1, 2019 at 12:30 AM Nitish Saboo <nitish...@gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I want to convert *C.char to array of strings in Go.
>>>>>> I want to do this because I want the first word from the
>>>>>> string.Strings are getting appended to *C.char and I want the first word
>>>>>> of
>>>>>> the string.
>>>>>> I am doing it using 'strings.Split(C.GoString(*C.char))[0]', but it
>>>>>> is giving error.
>>>>>> Can someone correct me here ?
>>>>>>
>>>>>> Thanks
>>>>>>
>>>>>> --
>>>>>> You received this message because you are subscribed to the Google
>>>>>> Groups "golang-nuts" group.
>>>>>> To unsubscribe from this group and stop receiving emails from it,
>>>>>> send an email to golan...@googlegroups.com.
>>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>>
>>>>> --
>>>> You received this message because you are subscribed to the Google
>>>> Groups "golang-nuts" group.
>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>> an email to golang-nuts+unsubscr...@googlegroups.com.
>>>> For more options, visit https://groups.google.com/d/optout.
>>>>
>>>
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
