freebsd man page for utrace

UTRACE(2)						      BSD System Calls Manual							 UTRACE(2)

NAME
     utrace -- insert user record in ktrace log

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/param.h>
     #include <sys/time.h>
     #include <sys/uio.h>
     #include <sys/ktrace.h>

     int
     utrace(const void *addr, size_t len);

DESCRIPTION
     Adds a record to the process trace with information supplied by user.  The record contains len bytes from memory pointed to by addr.  This
     call only has an effect if the calling process is being traced.

RETURN VALUES
     Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the
     error.

ERRORS
     [EINVAL]		Specified data length len was bigger than KTR_USER_MAXLEN.

     [ENOMEM]		Insufficient memory to honor the request.

     [ENOSYS]		Currently running kernel was compiled without ktrace(2) support (options KTRACE).

SEE ALSO
     kdump(1), ktrace(1), ktrace(2)

HISTORY
     The utrace() system call first appeared in FreeBSD 2.2.

BSD
								 November 1, 2014							       BSD