Array of buffer always changing values - arrays

Question

I have this code for verify what's in the array buffer, but i'm always getting different values on array and it makes my program getting a 56( 8 on ascii) when its not supose too, can somebody helps ?
This sends a buffer for socket to be read on file 1:
void send_stream(char buff[], int sockfdes)
{
if (write(sockfdes, buff, strlen(buff) + 1) == -1) {
perror("ERROR: envia_stream: simulador");
}
}
void prepare_message(int tipo, int id)
{
char buff[3];
buff[1] = id;
switch (tipo)
{
case CRIACAO_P:
buff[0] = '1';
//buff[2] = tempo; //HORA
send_stream(buff, sockfd);
break;
}
this file 2 read from socket and put in buffer:
char buffer[5];
while(1)
{
read(novosockfd, buffer, sizeof(buffer));
if (buffer[0] == '8')//FIM
{
printf("Buffer[0]: %d \n", buffer[0]);
printf("Buffer[1]: %d \n", buffer[1]);
printf("Buffer[2]: %d \n", buffer[2]);
printf("Buffer[3]: %d \n", buffer[3]);
printf("Buffer[4]: %d \n", buffer[4]);
printf("\nSimulação terminou\n");
break;
}
}
}

Answer 1

firstly you should tell us from where are you reading from, if you are reading from a socket, trying to implement a server or are you reading from a local socket?
Also, you should also check for the return type, like this:
if ( (read(novosockfd, buffer, sizeof(buffer)) <= 0 ) {
perror("error in read");
} else
{
//code to run if the read did not failed;
}
Note that for perror to work you have to #include
perror will automatically print the message in "" followed by the error description in the console. After you do all this, come and tell us more details.
Take not that if you do not check for failure in read, your code continues to get executed.

Answer 2

Judging by your update, you are first writing a buffer of size 4 bytes and reading for a buffer of 5 bytes, note that reading from a socket blocks until receiving the specified size in buffer, hence if you send 4 bytes to that socket, you can't expect to be able to read 5 bytes. So in order to be able to send the message, you should have char buff[4] declared in preare_message() instead of char buff[3], and also the parameter for the size of the message in the method write(int fildes, const void *buf, size_t nbytes) is of type size_t, so you should use : write(sockfdes, buff, sizeof(char) * strlen(buffer) + 1);
And you are also assigning id(int) into a char buffer.