.TH ph_change 3 "Oct 2002" "University of Illinois" "C Library Calls"
.SH NAME
ph_change, ph_add, ph_delete \- modify data on PH server
.SH SYNOPSIS
.B #include <phclient.h>
.P
.BI "int ph_change(PH *" ph ", struct ph_fieldselector " query "[],"
.BI "struct ph_fieldselector " change "[], int " flags ");"
.br
.BI "int ph_add(PH *" ph ", struct ph_fieldselector " fields "[]);"
.br
.BI "int ph_delete(PH *" ph ", struct ph_fieldselector " query "[]);"
.SH VERSION
This man page documents version 1.2 of \fBlibphclient\fP.
.SH DESCRIPTION
The \fBph_change\fP() function changes data on the PH server associated
with the \fBPH\fP handle \fIph\fP.  The \fIquery\fP argument selects which
entries will be changed in the same manner as for the \fBph_query\fP()
function.  The \fIchange\fP argument is an array of changes to make
on the server.  Each element of the array is a structure with three
fields: \fIfield\fP (the name of the field to modify encoded as a
string), \fIoperation\fP (a character value which must be set to '='),
and \fIvalue\fP (a string value to set the field to).  The last element
in the array must be set to all zeros.  If the \fIflags\fP argument is
set to \fBPH_CHANGE_FORCE\fP, the "force" clause is used instead of the
"make" clause when sending the change command to the server.

The \fBph_add\fP() function adds a new PH entry whose contents are specified
in \fIfields\fP.  This data is encoded just as the \fIchange\fP argument
to \fBph_change\fP() above.

The \fBph_delete\fP() function deletes entries from the PH server.  The
\fIquery\fP argument selects which entries will be deleted in the same
manner as for the \fBph_query\fP() function.
.SH RETURN VALUE
On success, the \fBph_change\fP() and \fBph_delete\fP() functions return
the number of entries changed or deleted, or \fIPH_ERR_DATAERR\fP if the
supplied field data is invalid.

All of the functions described here return \fIPH_ERR_NOTLOG\fP if no user
is logged in, and \fIPH_ERR_READONLY\fP if the server is in read-only
mode.  On error, they return -1 and set \fIerrno\fP.
.SH ERRORS
The functions describe here will fail with \fBEINVAL\fP if they receive
an unexpected response code from the server.  In addition, they may fail
with any error from the functions \fIread\fP() or \fIwrite\fP().
.SH SEE ALSO
.BR read (2),
.BR write (2),
.BR ph_query (3),
.BR ph_open (3)