mmap2 could be helpful. The mmap2() system call provides the same interface as mmap(), except that the final argument specifies the offset into the file in 4096-byte units (instead of bytes, as is done by mmap()). This enables applications that use a 32-bit off_t to map large files (up to 2^44 bytes).
https://man7.org/linux/man-pages/man2/mmap2.2.html But it is not yet implemented. FPC 3.0.4 Am Samstag, 21. November 2020, 13:31:22 CET schrieb Rainer Stratmann via fpc- pascal: > I watched the syscalls with strace and my assumption was confirmed. > > function Fpmmap( start: pointer; len: size_t; prot: cint; flags: cint; > fd:cint; offst: off_t ):pointer; > > My offst value for fpmmap is $100000000. > > strace output: > > mmap(NULL, 1920000, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_32BIT, 3, 0) = -1 > EINVAL > > Here the value is 0. > > It is likely that the offst value is stripped to 32 bit before passed to the > mmap syscall. > > > > Am Samstag, 21. November 2020, 01:15:20 CET schrieb Alexander Grotewohl via > > fpc-pascal: > > It would seem C handles this at compile time with a define.. mapping mmap > > to mmap64. Which would almost seem to imply you'd end up with a 32 bit > > binary that would only work on 64 bit systems. I'm not really sure how > > this would work for Pascal. You could start by looking in the file listed > > in the fpmmap docs you posted. My guess is the easiest answer is > > "distribute both 32 and 64 bit versions," but that doesn't help when you > > need to test the 32 bit one.. > > > > -- > > Alexander Grotewohl > > https://dcclost.com > > > > -- > > Alexander Grotewohl > > https://dcclost.com > > ________________________________ > > From: fpc-pascal <fpc-pascal-boun...@lists.freepascal.org> on behalf of > > Rainer Stratmann via fpc-pascal <fpc-pascal@lists.freepascal.org> Sent: > > Friday, November 20, 2020 6:33:51 PM > > To: fpc-pascal@lists.freepascal.org <fpc-pascal@lists.freepascal.org> > > Cc: Rainer Stratmann <rainerstratm...@t-online.de> > > Subject: [fpc-pascal] fpmmap problem 64 bit linux > > > > A 32 bit freepascal program on a 32 bit Linux Debian system is working > > properly. It uses fpmmap for getting the adress of a kms framebuffer. > > > > The same 32 bit program on a 64 bit Linux Debian system *** is not > > working. > > When it comes to the fpmmap it gives an error: > > > > Sys_EINVAL > > > > One of the record fields Start, length or offset is invalid. > > > > https://www.freepascal.org/docs-html/rtl/baseunix/fpmmap.html > > > > I figured out that it likely can only be the offset value since start and > > length are always the same. > > > > The offset value I got from a previous DRM function. > > > > On the 32 bit System this offset value is $10000000 (fits in 32 bit) > > And on the 64 bit System this offset value is $100000000 (does not fit in > > 32 bit). > > > > Can it be possible that the fpmmap function strips the offset value to 32 > > bit? Is there another way to call fpmmap more directly? > > What does fpmmap exactly? > > Where can I research? > > > > > > *** > > dpkg --add-architecture i386 > > apt-get update > > apt-get install libc6-i386 > > > > > > _______________________________________________ > > fpc-pascal maillist - fpc-pascal@lists.freepascal.org > > https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal > > _______________________________________________ > fpc-pascal maillist - fpc-pascal@lists.freepascal.org > https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
