Send data over sockets from Java program to C program

Question

I'm trying to send data over network from a Java program to a C program. But I don't know which type of data to use. I tried with a char.

Here is my Java code :

DataOutputStream dos = new DataOutputStream(sock.getOutputStream());
char c = 'c';
dos.writeChar(c);

And my C code :

char buffer[256];
bzero(buffer, 256);
read(newsockfd, buffer, 255);
printf("Here is the message: %c\n", buffer[0]);

"Here is the message" print nothing. I don't know if buffer[0] is empty or if the type is not compatible.

Yes I can use Json, but I just have an Int so send. I think it would be too heavy and complicated just for that, isn't ? — iAmoric
– iAmoric, Commented Mar 29, 2017 at 8:53
How about: OutputStream os = sock.getOutputStream(); os.write((byte) c); — ghchoi
– ghchoi, Commented Mar 29, 2017 at 8:56
I think DataOutputSteam is a Wrapper for easy communication for Java. To communicate with another program of different language, it would better to use the most primitive stream. — ghchoi
– ghchoi, Commented Mar 29, 2017 at 9:00

p0kR · Accepted Answer · 2017-03-29 10:22:16Z

2

in java a char is two bytes, you may use the java type "byte" to just send one byte. Or you have to support the two-byte character (unicode) sent by Java, to be printed in C.

Yet I did not have the time to check the rest of your code, but this might be a start.

answered Mar 29, 2017 at 10:22

p0kR

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