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.TH "__STRNCPY_FROM_USER" 9 "August 2005" "Kernel Hackers Manual" "LINUX"
.SH NAME
__strncpy_from_user \- Copy a NUL terminated string from userspace, with less checking.
.SH "SYNOPSIS"
.ad l
.hy 0
.HP 28
long\ \fB__strncpy_from_user\ \fR\ (char\ *\ \fIdst\fR, const\ char\ __user\ *\ \fIsrc\fR, long\ \fIcount\fR);
.ad
.hy

.SH "ARGUMENTS"

.TP
\fIdst\fR
Destination address, in kernel space\&. This buffer must be at least \fIcount\fR bytes long\&.

.TP
\fIsrc\fR
Source address, in user space\&.

.TP
\fIcount\fR
Maximum number of bytes to copy, including the trailing NUL\&.

.SH "DESCRIPTION"

.PP
Copies a NUL\-terminated string from userspace to kernel space\&. Caller must check the specified block with \fBaccess_ok\fR before calling this function\&.

.PP
On success, returns the length of the string (not including the trailing NUL)\&.

.PP
If access to userspace fails, returns \-EFAULT (some data may have been copied)\&.

.PP
If \fIcount\fR is smaller than the length of the string, copies \fIcount\fR bytes and returns \fIcount\fR\&.