gspool_jobdata - retrieve the data for a job as a stream
FILE *gspool_jobdata(const int fd, const unsigned flags, const slotno_t slotno)
int gspool_jobdata(const int fd, const int outfile, int (*func)(int,void*,unsigned), const unsigned flags, const slotno_t slotno)
The function gspool_jobdata() is used to retrieve the job file of a job.
fd is a file descriptor previously returned by gspool_open. flags
is zero, or GSPOOL_FLAG_IGNORESEQ
to ignore changes since the job
list was last read.
slotno is the slot number corresponding to the job previously returned by functions such as gspool_joblist or gspool_jobfindslot.
The result is a FILE
pointer which can be used with all standard
I/O input functions such as fgets(3)
, getc(3)
etc. At the end of the
data fclose(3)
must be called. For reasons of sychronisation the file
should be read to the end before other operations are attempted.
If an error is detected, gspool_jobdata returns NULL
and an error
code is placed in the external variable gsapi_dataerror
.
The second format of the gspool_jobdata function is for use by Windows
programs, as there is no acceptable equivalent of the pipe(2)
construct.
The second argument outfile is (possibly) a file handle to the file from to which the job data is passed as the first argument to func.
The third argument func is a function with the same specifications
as write
, indeed it may very well be write
. The main reason for
doing it this way is that some versions of Windows do strange things
if write
is invoked from within a DLL.
Other aspects of the interface are similar to the Unix routine, apart
from the routine returning zero for success and an error code for
failure rather than a FILE*
or NULL
. For consistency with the
Unix version, the external variable gsapi_dataerror
is also
assigned any error code returned.
If an error is detected the external variable gsapi_dataerror
will
be set to the error code.
Error codes are listed in Chapter 3.
An example to retrieve the data for a job:
int fd, ret, ch; slotno_t slot, *list; FILE *inf;
fd = gspool_open("myhost", (char *) 0, 0); if (fd < 0) { /* error handling */ ... }
/* Select a job slot and assign this to "slot" */ .......
inf = gspool_jobdata(fd, 0, slot); if (!inf) { /* handle errors */ ... }
while ((ch = getc(inf)) != EOF) putchar(ch); fclose(inf); gspool_close(fd);
gspool_joblist(3)
,
gspool_jobread(3)
,
gspool_jobadd(3)
,
gspool_jobdel(3)
,
gspool_jobfind(3)
,
gspool_jobfindslot(3)
,
gspool_jobupd(3)
,
gspool_jobmon(3)
,
gspool_jobpbrk(3)
.
Copyright (c) 2009 Free Software Foundation, Inc. This is free software. You may redistribute copies of it under the terms of the GNU General Public License <http://www.gnu.org/licenses/gpl.html>. There is NO WARRANTY, to the extent permitted by law.
John M Collins, Xi Software Ltd.