2009.05.17 09:30 "Re: [Tiff] Potential problem in libtiff when compiled in MinGW", by Ari Jolma

Ari Jolma kirjoitti:

Bob Friesenhahn kirjoitti:

As I've explained in a GDAL bug report http://trac.osgeo.org/gdal/ticket/2649, it is not enough to use WIN32 and _MSC_VER to determine whether to use %I64 instead of %ll as MinGW uses msvcrt.dll but does not define _MSC_VER. This is an issue in several places in libtiff sources (tif_dumpmode.c, tif_luv.c, tif_lzw.c, tif_print.c, tif_read.c, tif_strip.c, and tif_thunder.c).

Have you verified that this is an actual problem? My experience with MinGW builds is that 'long long' works, including in printf type specifications. I am not sure how MinGW accomplishes that but MinGW does provide a thin library which could do transformations if required.

I have not, I'll try to put together a test. In the GDAL case there was a verifiable problem, whose investigation led me to infer that this is generally a problem, but admittably this may be a bit different. I'll be back later.

Here's a test:

#include "tiffiop.h"

main() {
    thandle_t fd;
    int i = 1;
    unsigned long long occ = 1;
    for (i = 1; i < 11; i++)
        occ *= 10;
    TIFFErrorExt(fd, "module", "test unsigned long long with I64:
%I64u", occ);
    TIFFErrorExt(fd, "module", "test unsigned long long with ll: %llu",
occ);
}

testing:

ajolma@MOON /c/dev/libtiff/libtiff
$ gcc test.c -I libtiff/ -L libtiff/.libs/ -ltiff

ajolma@MOON /c/dev/libtiff/libtiff
$ ./a.exe
module: test unsigned long long with I64: 10000000000.
module: test unsigned long long with ll: 1410065408.

i.e., %ll does not work but %I64 works in MinGW. This is because MinGW uses msvcrt.dll, which is Microsoft, which.. see for example http://ascending.wordpress.com/2008/04/22/long-long-on-windows-dev-c-mingw/

Ari

Ari

Bob
--
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/

--
Prof. Ari Jolma
Environmental Management Information Technology
Teknillinen Korkeakoulu / Helsinki University of Technology
tel: +358 9 4511 address: POBox 5300, 02015 TKK, Finland
Email: ari.jolma at tkk.fi URL: http://geoinformatics.tkk.fi