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tcdrain()

Wait until all output has been transmitted to a device

Synopsis:

#include <termios.h>

int tcdrain( int fildes );

Arguments:

fildes

A file descriptor that's associated with the device that you want to wait for.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The tcdrain() function waits until all output has been physically transmitted to the device associated with fildes, or until a signal is received.

Returns:

0

Success.

-1

An error occurred (errno is set).

Errors:

EBADF

The argument fildes is invalid.

EINTR

A signal interrupted the operation.

ENOSYS

The resource manager associated with fildes doesn't support this call.

ENOTTY

The argument fildes doesn't refer to a terminal device.

Examples:

#include <termios.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>

int main( void )
  {
    int fildes;

    fildes = open( "/dev/ser1", O_RDWR );
    write( fildes, "ATH", 3 );

    /* Wait for data to transmit before returning */
    tcdrain( fildes );
    close( fildes );
    return EXIT_SUCCESS;
  }

Classification:

POSIX 1003.1

Safety:
Cancellation point	Yes
Interrupt handler	No
Signal handler	Yes
Thread	Yes

See also:

write()

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