libdill: Structured Concurrency for C


pfx_attach_mem - creates PFX protocol on top of underlying socket


#include <libdill.h>

int pfx_attach_mem(
    int s,
    void* mem);


PFX is a message-based protocol to send binary messages prefixed by 8-byte size in network byte order. The protocol has no initial handshake. Terminal handshake is accomplished by each peer sending eight 0xFF bytes.

This function instantiates PFX 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 pfx_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 PFX_SIZE bytes long and must not be deallocated before the object is closed.

The socket can be cleanly shut down using pfx_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 = pfx_attach(s);
msend(s, "ABC", 3, -1);
char buf[256];
ssize_t sz = mrecv(s, buf, sizeof(buf), -1);
s = pfx_detach(s, -1);


hclose(3) mrecv(3) mrecvl(3) msend(3) msendl(3) pfx_attach(3) pfx_detach(3)