libdill: Structured Concurrency for C


crlf_attach_mem - creates CRLF protocol on top of underlying socket


#include <libdill.h>

int crlf_attach_mem(
    int s,
    void* mem);


CRLF is a message-based protocol that delimits messages usign CR+LF byte sequence (0x0D 0x0A). In other words, it's a protocol to send text messages separated by newlines. The protocol has no initial handshake. Terminal handshake is accomplished by each peer sending an empty line.

This function instantiates CRLF protocol on top of the underlying protocol.

This function allows to avoid one dynamic memory allocation by storing the object in user-supplied memory. Unless you are hyper-optimizing use crlf_attach instead.

s: Handle of the underlying socket. It must be a bytestream protocol.

mem: The memory to store the newly created object. It must be at least CRLF_SIZE bytes long and must not be deallocated before the object is closed.

The socket can be cleanly shut down using crlf_detach function.

This function is not available if libdill is compiled with --disable-sockets option.


In case of success the function returns newly created socket handle. In case of error it returns -1 and sets errno to one of the values below.



int s = tcp_connect(&addr, -1);
s = crlf_attach(s);
msend(s, "ABC", 3, -1);
char buf[256];
ssize_t sz = mrecv(s, buf, sizeof(buf), -1);
s = crlf_detach(s, -1);


crlf_attach(3) crlf_detach(3) hclose(3) mrecv(3) mrecvl(3) msend(3) msendl(3)