Implementation was a little intrusive because there is no recovery from calling freopen() on stdout. This preliminary patch follows the recommendations of the C FAQ and introduces an explicit stream variable. I've only done light testing.
http://c-faq.com/stdio/undofreopen.html $ scanimage --batch 2> /dev/null | cat out1.pnm out2.pnm Cheers, Jeff --- /tmp/orig/sane-backends-1.0.23/frontend/scanimage.c 2014-05-12 13:44:40.000000000 -0700 +++ sane-backends-1.0.23/frontend/scanimage.c 2014-05-12 14:17:18.000000000 -0700 @@ -1124,7 +1124,8 @@ } static void -write_pnm_header (SANE_Frame format, int width, int height, int depth) +write_pnm_header (SANE_Frame format, int width, int height, int depth, + FILE *ofp) { /* The netpbm-package does not define raw image data with maxval > 255. */ /* But writing maxval 65535 for 16bit data gives at least a chance */ @@ -1135,20 +1136,20 @@ case SANE_FRAME_GREEN: case SANE_FRAME_BLUE: case SANE_FRAME_RGB: - printf ("P6\n# SANE data follows\n%d %d\n%d\n", width, height, + fprintf (ofp, "P6\n# SANE data follows\n%d %d\n%d\n", width, height, (depth <= 8) ? 255 : 65535); break; default: if (depth == 1) - printf ("P4\n# SANE data follows\n%d %d\n", width, height); + fprintf (ofp, "P4\n# SANE data follows\n%d %d\n", width, height); else - printf ("P5\n# SANE data follows\n%d %d\n%d\n", width, height, + fprintf (ofp, "P5\n# SANE data follows\n%d %d\n%d\n", width, height, (depth <= 8) ? 255 : 65535); break; } #ifdef __EMX__ /* OS2 - write in binary mode. */ - _fsetmode (stdout, "b"); + _fsetmode (ofp, "b"); #endif } @@ -1183,7 +1184,7 @@ } static SANE_Status -scan_it (void) +scan_it (FILE *ofp) { int i, len, first_frame = 1, offset = 0, must_buffer = 0, hundred_percent; SANE_Byte min = 0xff, max = 0; @@ -1273,10 +1274,10 @@ sanei_write_tiff_header (parm.format, parm.pixels_per_line, parm.lines, parm.depth, resolution_value, - icc_profile); + icc_profile, ofp); else write_pnm_header (parm.format, parm.pixels_per_line, - parm.lines, parm.depth); + parm.lines, parm.depth, ofp); } break; @@ -1397,7 +1398,7 @@ else /* ! must_buffer */ { if ((output_format == OUTPUT_TIFF) || (parm.depth != 16)) - fwrite (buffer, 1, len, stdout); + fwrite (buffer, 1, len, ofp); else { #if !defined(WORDS_BIGENDIAN) @@ -1408,7 +1409,7 @@ { if (len > 0) { - fwrite (buffer, 1, 1, stdout); + fwrite (buffer, 1, 1, ofp); buffer[0] = (SANE_Byte) hang_over; hang_over = -1; start = 1; @@ -1429,7 +1430,7 @@ len--; } #endif - fwrite (buffer, 1, len, stdout); + fwrite (buffer, 1, len, ofp); } } @@ -1453,10 +1454,10 @@ if (output_format == OUTPUT_TIFF) sanei_write_tiff_header (parm.format, parm.pixels_per_line, image.height, parm.depth, resolution_value, - icc_profile); + icc_profile, ofp); else write_pnm_header (parm.format, parm.pixels_per_line, - image.height, parm.depth); + image.height, parm.depth, ofp); #if !defined(WORDS_BIGENDIAN) /* multibyte pnm file may need byte swap to LE */ @@ -1474,11 +1475,11 @@ } #endif - fwrite (image.data, 1, image.height * image.width, stdout); + fwrite (image.data, 1, image.height * image.width, ofp); } /* flush the output buffer */ - fflush( stdout ); + fflush( ofp ); cleanup: if (image.data) @@ -1714,6 +1715,7 @@ SANE_Status status; char *full_optstring; SANE_Int version_code; + FILE *ofp; atexit (scanimage_exit); @@ -2236,12 +2238,15 @@ format = "out%d.pnm"; } + if (!batch) + ofp = stdout; + if (batch) fprintf (stderr, "Scanning %d pages, incrementing by %d, numbering from %d\n", batch_count, batch_increment, batch_start_at); - else if(isatty(fileno(stdout))){ + else if(isatty(fileno(ofp))){ fprintf (stderr,"%s: output is not a file, exiting\n", prog_name); exit (1); } @@ -2274,7 +2279,11 @@ { fprintf (stderr, "Batch terminated, %d pages scanned\n", (n - batch_increment)); - fclose (stdout); + if (ofp) + { + fclose (ofp); + ofp = NULL; + } break; /* get out of this loop */ } } @@ -2294,19 +2303,27 @@ { fprintf (stderr, "%s: sane_start: %s\n", prog_name, sane_strstatus (status)); - fclose (stdout); - break; + if (ofp) + { + fclose (ofp); + ofp = NULL; + break; + } } + /* write to .part file while scanning is in progress */ - if (batch && NULL == freopen (part_path, "w", stdout)) + if (batch) + ofp = fopen (part_path, "w"); + + if (batch && ofp == NULL) { fprintf (stderr, "cannot open %s\n", part_path); sane_cancel (device); return SANE_STATUS_ACCESS_DENIED; } - status = scan_it (); + status = scan_it (ofp); if (batch) { fprintf (stderr, "Scanned page %d.", n); @@ -2321,10 +2338,16 @@ if (batch) { /* close output file by redirecting, do not close - stdout here! */ - if (NULL == freopen ("/dev/null", "w", stdout)) + ofp here! */ + int r = -1; + if (ofp) { - fprintf (stderr, "cannot open /dev/null\n"); + r = fclose(ofp); + ofp = NULL; + } + if (0 != r) + { + fprintf (stderr, "cannot close image file\n"); sane_cancel (device); return SANE_STATUS_ACCESS_DENIED; } @@ -2338,13 +2361,19 @@ sane_cancel (device); return SANE_STATUS_ACCESS_DENIED; } + fprintf (stdout, "%s\n", path); + fflush (stdout); } } break; default: if (batch) { - fclose (stdout); + if (ofp) + { + fclose (ofp); + ofp = NULL; + } unlink (part_path); } break; --- /tmp/orig/sane-backends-1.0.23/frontend/stiff.c 2011-06-27 10:40:22.000000000 -0700 +++ sane-backends-1.0.23/frontend/stiff.c 2014-05-12 14:17:18.000000000 -0700 @@ -586,10 +586,10 @@ void sanei_write_tiff_header (SANE_Frame format, int width, int height, int depth, - int resolution, const char *icc_profile) + int resolution, const char *icc_profile, FILE *ofp) { #ifdef __EMX__ /* OS2 - write in binary mode. */ - _fsetmode(stdout, "b"); + _fsetmode(ofp, "b"); #endif switch (format) { @@ -597,14 +597,14 @@ case SANE_FRAME_GREEN: case SANE_FRAME_BLUE: case SANE_FRAME_RGB: - write_tiff_color_header (stdout, width, height, depth, resolution, icc_profile); + write_tiff_color_header (ofp, width, height, depth, resolution, icc_profile); break; default: if (depth == 1) - write_tiff_bw_header (stdout, width, height, resolution); + write_tiff_bw_header (ofp, width, height, resolution); else - write_tiff_grey_header (stdout, width, height, depth, resolution, icc_profile); + write_tiff_grey_header (ofp, width, height, depth, resolution, icc_profile); break; } } --- /tmp/orig/sane-backends-1.0.23/frontend/stiff.h 2011-06-27 10:40:22.000000000 -0700 +++ sane-backends-1.0.23/frontend/stiff.h 2014-05-12 14:17:18.000000000 -0700 @@ -17,4 +17,4 @@ void sanei_write_tiff_header (SANE_Frame format, int width, int height, int depth, - int resolution, const char *icc_profile); + int resolution, const char *icc_profile, FILE *ofp);
names-to-stdout-1.0.gz
Description: GNU Zip compressed data
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