![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to slowsend.c CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [Research Unix] / researchv10no / cmd / post.src / postio|
Return to slowsend.c CVS log | Up to [Research Unix] / researchv10no / cmd / post.src / postio |
1.1 root 1: /*
2: *
3: * Stuff that slows the transmission of jobs to PostScript printers. ONLY use it
4: * if you appear to be having trouble with flow control. The idea is simple - only
5: * send a significant amount of data when we're certain the printer is in the
6: * WAITING state. Depends on receiving status messages and only works when the
7: * program is run as a single process. What's done should stop printer generated
8: * XOFFs - provided our input buffer (ie. blocksize) is sufficiently small. Was
9: * originally included in the postio.tmp directory, but can now be requested with
10: * the -S option. Considered eliminating this code, but some printers still depend
11: * on it. In particular Datakit connections made using Datakit PVCs and DACUs seem
12: * to have the most problems. Much of the new stuff that was added can't work when
13: * you use this code and will be automatically disabled.
14: *
15: */
16:
17: #include <stdio.h>
18:
19: #include "gen.h"
20: #include "postio.h"
21:
22: extern char *block;
23: extern int blocksize;
24: extern int head;
25: extern int tail;
26: extern char *line;
27: extern char mesg[];
28: extern int ttyo;
29:
30: /*****************************************************************************/
31:
32: slowsend(fd_in)
33:
34: int fd_in; /* next input file */
35:
36: {
37:
38: /*
39: *
40: * A slow version of send() that's very careful about when data is sent to the
41: * printer. Should help prevent overflowing the printer's input buffer, provided
42: * blocksize is sufficiently small (1024 should be safe). It's a totally kludged
43: * up routine that should ONLY be used if you have constant transmission problems.
44: * There's really no way it will be able to drive a printer much faster that about
45: * six pages a minute, even for the simplest jobs. Get it by using the -S option.
46: *
47: */
48:
49: while ( readblock(fd_in) )
50: switch ( getstatus(0) ) {
51: case WAITING:
52: writeblock(blocksize);
53: break;
54:
55: case BUSY:
56: case IDLE:
57: case PRINTING:
58: writeblock(30);
59: break;
60:
61: case NOSTATUS:
62: case UNKNOWN:
63: break;
64:
65: case PRINTERERROR:
66: sleep(30);
67: break;
68:
69: case ERROR:
70: fprintf(stderr, "%s", mesg); /* for csw */
71: error(FATAL, "PostScript Error");
72: break;
73:
74: case FLUSHING:
75: error(FATAL, "Flushing Job");
76: break;
77:
78: case DISCONNECT:
79: error(FATAL, "Disconnected - printer may be offline");
80: break;
81:
82: default:
83: sleep(2);
84: break;
85: } /* End switch */
86:
87: } /* End of send */
88:
89: /*****************************************************************************/
90:
91: static writeblock(num)
92:
93: int num; /* most bytes we'll write */
94:
95: {
96:
97: int count; /* bytes successfully written */
98:
99: /*
100: *
101: * Called from send() when it's OK to send the next block to the printer. head
102: * is adjusted after the write, and the number of bytes that were successfully
103: * written is returned to the caller.
104: *
105: */
106:
107: if ( num > tail - head )
108: num = tail - head;
109:
110: if ( (count = write(ttyo, &block[head], num)) == -1 )
111: error(FATAL, "error writing to %s", line);
112: else if ( count == 0 )
113: error(FATAL, "printer appears to be offline");
114:
115: head += count;
116: return(count);
117:
118: } /* End of writeblock */
119:
120: /*****************************************************************************/
121:
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.