How can i print a variable from another function? - c

Question

I try to make a ssh remote command with a part of code founded in libssh examples and i try to print output outside executing function like this
in int main();
printf("Server output: %s", nbytes);
int exec_uname(ssh_session session) {
ssh_channel channel;
int rc;
channel = ssh_channel_new(session);
if (channel == NULL) return SSH_ERROR;
rc = ssh_channel_open_session(channel);
if (rc != SSH_OK) {
ssh_channel_free(channel);
return rc;
}
//Once a session is open, you can start the remote command with ssh_channel_request_exec():
rc = ssh_channel_request_exec(channel, "uname -a");
if (rc != SSH_OK) {
ssh_channel_close(channel);
ssh_channel_free(channel);
return rc;
}
//If the remote command displays data, you get them with ssh_channel_read(). This function returns the number of bytes read. If there is no more data to read on the channel, this function returns 0, and you can go to next step. If an error has been encountered, it returns a negative value:
char buffer[256];
int nbytes;
nbytes = ssh_channel_read(channel, buffer, sizeof(buffer), 0);
while (nbytes > 0) {
if (fwrite(buffer, 1, nbytes, stdout) != nbytes) {
ssh_channel_close(channel);
ssh_channel_free(channel);
return SSH_ERROR;
}
nbytes = ssh_channel_read(channel, buffer, sizeof(buffer), 0);
}
if (nbytes < 0) {
ssh_channel_close(channel);
ssh_channel_free(channel);
return SSH_ERROR;
}
//Once you read the result of the remote command, you send an end-of-file to the channel, close it, and free the memory that it used:
ssh_channel_send_eof(channel);
ssh_channel_close(channel);
ssh_channel_free(channel);
return SSH_OK;
}

Answer 1

You can't access a local variable outside a function. You either declare that in a broader scope, like global, which is a last-resort, or pass it in to be populated.
For example:
int exec_uname(ssh_session session, int* bytes) {
// ... code
// Push back to caller
*bytes = nbytes;
}
So when called:
int nbytes;
int result = exec_uname(session, &nbytes);
printf("Server output: %d", nbytes);
You'll still need to check result to be sure the function terminated properly or the value in nbytes will not be usable.