Passing []byte from golang to char * C.

[aditi.bh...@gmail.com]

I have a byte array of image in golang , i have to pass this array to my C function as char* . I did he following ,

         data, err := ioutil.ReadAll(out.Body)

         str := fmt.Sprintf("%s",data)

         s:=C.main1(C.CString(str))

         s:=C.main1((*C.char)(unsafe.Pointer(&data[0])))

but both the technique doesn't work. All i m receiving in my C function is some garbage value of length 4. 

[andrey mirtchovski]

can you show us a complete example with a stub C function? in
particular the conversion to (*C.char) from unsafe.Pointer(&data[0])
should work. compare the first four bits at that address with the
first four bits you're receiving on the C side. they should be
identical. e.g.: https://play.golang.org/p/sqP12_nJNF

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[Tamás Gulácsi]

Both should work. What is your C function?

[Aditi Bhiwaniwala]

the error occur because there is 0 in my byte array . Do i need to encode it then?

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[Tamás Gulácsi]

C strings are 0-terminated. Either encode 0 (byte) values, or call with pointer to first byte, and the length.