libdill: Structured Concurrency for C

NAME

chsend - sends a message to a channel

SYNOPSIS

#include <libdill.h>

int chsend(
    int ch,
    const void* val,
    size_t len,
    int64_t deadline);

DESCRIPTION

Sends a message to a channel.

The size of the message sent to the channel must match the size of the message requested from the channel. Otherwise, both peers fail with EMSGSIZE error.

If there's no receiver for the message, the function blocks until one shows up or until the deadline expires.

ch: The channel.

val: Pointer to the value to send to the channel.

len: Size of the value to send to the channel, in bytes.

deadline: A point in time when the operation should time out, in milliseconds. Use the now function to get your current point in time. 0 means immediate timeout, i.e., perform the operation if possible or return without blocking if not. -1 means no deadline, i.e., the call will block forever if the operation cannot be performed.

RETURN VALUE

In case of success the function returns 0. In case of error it returns -1 and sets errno to one of the values below.

ERRORS

EBADF: Invalid handle.
ECANCELED: Current coroutine was canceled.
EINVAL: Invalid argument.
EMSGSIZE: The peer expected a different message size.
ENOTSUP: The handle does not support this operation.
EPIPE: Channel has been closed with chdone.
ETIMEDOUT: Deadline was reached.

EXAMPLE

int val = 42;
int rc = chsend(ch, &val, sizeof(val), now() + 1000);
if(rc != 0) {
    perror("Cannot send message");
    exit(1);
}
printf("Value %d sent successfully.\n", val);