Wireshark mailing list archives
Re: [Wireshark-commits] rev 51169: / /trunk/epan/: app_mem_usage.c
From: Guy Harris <guy () alum mit edu>
Date: Tue, 6 Aug 2013 17:19:23 -0700
On Aug 6, 2013, at 3:57 PM, Dirk Jagdmann <doj () cubic org> wrote:
If not, would an lseek() followed by a read() do just as well?No. lseek() and read() modify the file position/offset. pread() however does *not* modify it. So to emulate pread() you would need something like:
If you do an absolute lseek() before each read(), and no other code uses the file descriptor, an lseek() followed by a read() *would* do as well. The only things the routine in question does with the FD (which is static to the routine) are (attempt to) open it if it's not already open; read it with ret = pread(fd, buf, sizeof(buf)-1, 0); if (ret <= 0) return FALSE; so that could be replaced by if (lseek(fd, 0, SEEK_SET) == -1) return FALSE; ret = read(fd, buf, sizeof(buf)-1); if (ret <= 0) return FALSE; ___________________________________________________________________________ Sent via: Wireshark-dev mailing list <wireshark-dev () wireshark org> Archives: http://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-request () wireshark org?subject=unsubscribe
Current thread:
- Re: [Wireshark-commits] rev 51169: / /trunk/epan/: app_mem_usage.c Guy Harris (Aug 06)
- Re: [Wireshark-commits] rev 51169: / /trunk/epan/: app_mem_usage.c Evan Huus (Aug 06)
- Re: [Wireshark-commits] rev 51169: / /trunk/epan/: app_mem_usage.c Jakub Zawadzki (Aug 06)
- Re: [Wireshark-commits] rev 51169: / /trunk/epan/: app_mem_usage.c Evan Huus (Aug 06)
- Re: [Wireshark-commits] rev 51169: / /trunk/epan/: app_mem_usage.c Evan Huus (Aug 06)
- Re: [Wireshark-commits] rev 51169: / /trunk/epan/: app_mem_usage.c Jakub Zawadzki (Aug 06)
- Re: [Wireshark-commits] rev 51169: / /trunk/epan/: app_mem_usage.c Dirk Jagdmann (Aug 06)
- Re: [Wireshark-commits] rev 51169: / /trunk/epan/: app_mem_usage.c Guy Harris (Aug 06)
- Re: [Wireshark-commits] rev 51169: / /trunk/epan/: app_mem_usage.c Evan Huus (Aug 06)