Messages in this thread | | | Date | Wed, 25 Oct 2000 10:19:23 +0200 | From | Gábor Lénárt <> | Subject | mmap() question |
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Hi,
Sorry for my stupid question, but I haven't got idea what the problem can be, and maybe you can help me. See the following fragment of C code:
videobuffer=mmap(0,MAX_VIDEO_PACKET_SIZE,PROT_READ|PROT_WRITE,MAP_ANON|MAP_SHARED,-1,0); if (videobuffer==(void*)-1) { perror("mmap()"); exit(1); }
This will return with Invalid argument. The nice this is that this code runs happyly with 2.4.x-pre kernels but not with my 2.2.17 or 2.2.18pre15.
Maybe because of not page aligned size, so I modify my code: I defined MAX_VIDEO_PACKET_SIZE to 4096 for testing (on PC page size is 4096 bytes, and getpagesize() returns with this as well, I checked).
The result is the same ! I don't understand what the problem can be ...
I tried with opening /dev/zero with O_RDWR mode than mapping that, but that gave me the same result ;-(
I'm totally confused. Can someone help, please ?
- Gabor
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