tcflow()
QNX SDP8.0C Library ReferenceAPIDeveloper
Perform a flow-control operation on a data stream
Synopsis:
#include <termios.h>
int tcflow( int filedes,
int action );
Arguments:
- filedes
- A file descriptor that's associated with the data stream that you want to perform the operation on.
- action
- The action you want to perform; see below.
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The tcflow() function performs a flow-control operation on the data stream associated with filedes, depending on the values in action.
At least the following actions are defined in <termios.h>:
- TCOOFF
- Use software flow control to suspend output on the device associated with filedes.
- TCOOFFHW
- Use hardware flow control to suspend output on the device associated with filedes.
- TCOON
- Use software flow control to resume output on the device associated with filedes.
- TCOONHW
- Use hardware flow control to resume output on the device associated with filedes.
- TCIOFF
- Cause input to be flow-controlled by sending a STOP character immediately across the communication line associated with filedes, (that is, software flow control).
- TCIOFFHW
- Cause input to be flow-controlled by using hardware control.
- TCION
- Resume input by sending a START character immediately across the communication line associated with filedes (that is, software flow control).
- TCIONHW
- Cause input to be resumed by using hardware flow control.
Returns:
- 0
- Success.
- -1
- An error occurred (errno is set).
Errors:
- EBADF
- Invalid filedes argument.
- EINVAL
- Invalid action argument.
- ENOSYS
- The resource manager associated with filedes doesn't support this call.
- ENOTTY
- The argument filedes doesn't refer to a terminal device.
Examples:
#include <termios.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
int main( void )
{
int fd;
fd = open( "/dev/ser1", O_RDWR );
/* Resume output on flow-controlled device */
tcflow( fd, TCOON );
close( fd );
return EXIT_SUCCESS;
}
Classification:
Safety: | |
---|---|
Cancellation point | No |
Signal handler | Yes |
Thread | Yes |
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