FIONREAD
QNX SDP8.0Devctl and Ioctl CommandsDeveloper
Determine the number of characters waiting to be read
Synopsis:
#include <sys/ioctl.h>
#define FIONREAD _IOR('f', 127, int)
Arguments to ioctl():
Argument | Value |
---|---|
fd | A file descriptor that you obtained by opening the device |
request | FIONREAD |
Additional argument | A pointer to an int |
Description:
This command determine the number of characters waiting to be read. It's also implemented as the DCMD_CHR_ISCHARS devctl() command.
Note:
This command is for internal use, and you shouldn't use it directly.
Instead use the
tcischars()
cover function.
Input:
None.
Output:
The number of characters.
See also:
ioctl() in the QNX OS C Library Reference
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