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)\n", 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