ureadc(D3)ureadc(D3)NAMEureadc - copy a character to space described by uio(D4) structure
SYNOPSIS
#include <sys/uio.h>
#include <sys/ddi.h>
int ureadc(int c, uio_t *uiop);
Arguments
c The character to be copied.
uiop Pointer to the uio structure.
DESCRIPTIONureadc copies the character c into the space described by the uio
structure pointed to by uiop.
The uio_segflg member of the uio structure specifies the type of space to
which the copy is made. If uio_segflg is set to UIO_SYSSPACE the
character is copied to a kernel address. If uio_segflg is set to
UIO_USERSPACE the character is copied to a user address.
If the character is successfully copied, ureadc updates the appropriate
members of the uio and iovec(D4) structures to reflect the copy
(uio_offset and iov_base are incremented and uio_resid and iov_len are
decremented).
Return Values
ureadc returns 0 on success or an error number on failure.
USAGE
Level
Base only if uio_segflg is set to UIO_USERSPACE.
Base or Interrupt if uio_segflg is set to UIO_SYSSPACE.
Synchronization Constraints
May sleep if uio_segflg is set to UIO_USERSPACE.
Driver-defined basic locks and read/write locks may be held across calls
to this function if uio_segflg is UIO_SYSSPACE but may not be held if
uio_segflg is UIO_USERSPACE.
Driver-defined sleep locks may be held across calls to this function
regardless of the value of uio_segflg.
Warnings
When holding locks across calls to this function, multithreaded drivers
must be careful to avoid creating a deadlock. During the data transfer,
page fault resolution might result in another I/O to the same device.
For example, this could occur if the driver controls the disk drive used
as the swap device.
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ureadc(D3)ureadc(D3)REFERENCESiovec(D4), uio(D4), uiomove(D3), uwritec(D3)
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