xpaopen(3) SAORD Documentation xpaopen(3)NAME
XPAOpen - allocate a persistent client handle
SYNOPSIS
#include <xpa.h>
XPA XPAOpen(char *mode);
DESCRIPTION
XPAOpen() allocates a persistent XPA struct that can be used with calls to XPAGet(), XPASet(), XPAInfo(), XPAGetFd(), and XPASetFd(). Per-
sistence means that a connection to an XPA server is not closed when one of the above calls is completed but will be re-used on successive
calls. Using XPAOpen() therefore saves the time it takes to connect to a server, which could be significant with slow connections or if
there will be a large number of exchanges with a given access point. The mode argument currently is ignored ("reserved for future use").
An XPA struct is returned if XPAOpen() was successful; otherwise NULL is returned. This returned struct can be passed as the first argument
to XPAGet(), etc. Those calls will update the list of active XPA connections. Already connected servers (from a previous call) are left
connected and new servers also will be connected. Old servers (from a previous call) that are no longer needed are disconnected. The con-
nected servers will remain connected when the next call to XPAGet() is made and connections are once again updated.
Example -
#include <xpa.h>
XPA xpa;
xpa = XPAOpen(NULL);
SEE ALSO
See xpa(7) for a list of XPA help pages
version 2.1.14 June 7, 2012 xpaopen(3)
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xpasetfd(3) SAORD Documentation xpasetfd(3)NAME
XPASetFd - send data from stdin to one or more XPA servers
SYNOPSIS
#include <xpa.h>
int XPASetFd(XPA xpa,
char *template, char *paramlist, char *mode,
int fd, char **names, char **messages, int n)
DESCRIPTION
Read data from a standard I/O fd and send it to one or more XPA servers whose class:name identifier matches the specified template.
A template of the form "class1:name1" is sent to the XPA name server, which returns a list of at most n matching XPA servers. A connection
is established with each of these servers and the paramlist string is passed to the server as the data transfer request is initiated. If an
XPA struct is passed to the call, then the persistent connections are updated as described above. Otherwise, temporary connections are made
to the servers (which will be closed when the call completes).
The XPASetFd() routine then reads bytes from the specified fd until EOF and sends these bytes to the XPA servers. The final parameter n
specifies the maximum number of servers to contact. A string containing the class:name and ip:port of each server is returned in the name
array. If a given server returned an error, then the error message will be stored in the associated element of the messages array. NB: if
specified, the name and messages arrays must be of size n or greater.
The return value will contain the actual number of servers that were processed. This value thus will hold the number of valid entries in
the names and messages arrays, and can be used to loop through these arrays. In names and/or messages is NULL, no information is passed
back in that array.
The mode string is of the form: "key1=value1,key2=value2,..." The following keywords are recognized:
key value default explanation
---------------------------------
ack true/false true if false, don't wait for ack from server (after callback completes)
verify true/false false send buf from XPASet[Fd] to stdout
The ack keyword is useful in cases where one does not want to wait for the server to complete, e.g. is a lot of processing needs to be done
on the passed data or when the success of the server operation is not relevant to the client.
Example -
#include <xpa.h>
#define NXPA 10
int i, got;
int fd;
char *names[NXPA];
char *messages[NXPA];
fd = open(...);
got = XPASetFd(NULL, "ds9", "fits", NULL, fd, names, messages, NXPA);
for(i=0; i<got; i++){
if( messages[i] != NULL ){
/* error processing */
fprintf(stderr, "ERROR: %s (%s)
", messages[i], names[i]);
}
if( names[i] )
free(names[i]);
if( messages[i] )
free(messages[i]);
}
SEE ALSO
See xpa(7) for a list of XPA help pages
version 2.1.14 June 7, 2012 xpasetfd(3)