ProSoft Technology MVI69-ADM - Manual (Page 251)

MVI-ADM ♦ 'C' Programmable Serial Port Library Functions
'C' Programmable Application Development Module Developer's Guide
ProSoft Technology, Inc. Page 251 of 342
February 20, 2013
9.4 Serial Port API Communications
MVIsp_Putch
Syntax
int MVIsp_Putch(int comport, BYTE ch, DWORD timeout);
Parameters
comport port to which data is to be sent
ch character to be sent
timeout amount of time to wait to send character
Description
This function transmits a single character across a serial port. comport must be
previously opened with MVIsp_Open.
ch is the byte to be sent.
All data sent to a port is queued before transmission across the serial port.
Therefore, some delay may occur between the time after this function returns
and the actual time that the character is transmitted across the serial line. This
function attempts to insert the character into the transmission queue, and return
values correspond accordingly.
timeout specifies the amount of time in milliseconds to wait. If timeout is
TIMEOUT_ASAP, the function will return immediately if the character cannot be
queued immediately. If timeout is TIMEOUT_FOREVER, the function will not
return until the character is queued successfully.
If the character can be queued immediately, MVIsp_Putch returns
MVI_SUCCESS. If the character cannot be queued immediately, MVIsp_Putch
tries to queue the character until the timeout elapses. If the timeout elapses
before the character can be queued, MVI_ERR_TIMEOUT is returned.
Note: If handshaking is enabled and the receiving serial device has paused transmission, timeouts
may occur after the queue becomes full.
Return Value
MVI_SUCCESS the char was sent successfully
MVI_ERR_NOACCESS comport has not been opened
MVI_ERR_BADPARAM invalid parameter
MVI_ERR_TIMEOUT timeout elapsed before character sent
Example
if (MVIsp_Putch(COM1, ';', 1000L) != MVI_SUCCESS)
printf("Semicolon could not be sent in 1 second\n");
See Also
MVIsp_GetCh (page 252)
MVIsp_Puts (page 253)