DOKK / manpages / debian 10 / libowfat-dev / io_block.3.en
io_block(3) Library Functions Manual io_block(3)

io_block - switch to blocking I/O

#include <io.h>

void io_block(int64 fd);

io_block puts UNIX descriptor fd into ``blocking mode.''

File descriptors are normally in blocking mode, except if they come from accept() or io_accept() and the listening socket was in non-blocking mode.

io_nonblock(3)