I am trying to understand the usage of socket APIs (recv, send, select, close, etc) on parallel threads. That means using one socket file descriptor on two parallel threads. I have gone through this question. But still I am not able to find any standard doc which explains the usage of socket APIs in multiple thread. Even opengroup man page is not telling anything about this.
I also want to know whether below listed parallel thread usage scenarios are valid in POSIX socket APIs
1) Calling recv and send in two parallel threads
int main_thread() {
fd = do_connect(); //TCP or UDP
spawn_thread(recv_thread, fd);
spwan_thread(send_thread, fd);
...
}
int recv_thread(fd) {
while(1) {
recv(fd, ..)
...
}
}
int send_thread(fd) {
while(1) {
send(fd, ..)
...
}
}
2) Calling recv and send with select in two parallel threads
int recv_thread(fd) {
while(1) {
select(fd in readfd)
recv(fd, ..)
...
}
}
int send_thread(fd) {
while(1) {
select(fd in write)
send(fd, ..)
...
}
}
3) Calling recv and send with setsockopt, ioctl, fcntl in two paralle threads
int recv_thread(fd) {
int flag = 1
while(1) {
ioctl(fd, FIONBIO, &flag); //enable non block
recv(fd, ..)
flag = 0;
ioctl(fd, FIONBIO, &flag); //disable non block
...
}
}
int send_thread(fd) {
while(1) {
select(fd in write)
send(fd, ..)
...
}
}