Changes between Version 13 and Version 14 of PortingTips
- Timestamp:
- Jun 26, 2017, 2:15:17 PM (7 years ago)
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PortingTips
v13 v14 80 80 Note that this will cause **all** applications linked against `LIBCxyz.dll` to create a log file named `libc-ABCD.log` in the application's current directory where ABCD is a hex number of a running process. Given that we disabled all logging by `SET LIBC_LOGGING=-ALL` in CONFIG.SYS, these files will only contain a small log header and won't grow at runtime — this is done to avoid excessive logging for unneeded applications and unnecessary slowdown caused by this logging. 81 81 82 In order to get anything useful in the log file, you need to enable logging for your application. This is done by overriding the `LIBC_LOGGING` environment va lue before starting it. To enable full logging, just do82 In order to get anything useful in the log file, you need to enable logging for your application. This is done by overriding the `LIBC_LOGGING` environment variable before starting it. To enable full logging, just do 83 83 {{{ 84 84 SET LIBC_LOGGING=+ALL … … 91 91 If you want to go back to the normal LIBC version, just unlock `LIBCxyz.dll`, rename it back to `LIBCxyz.logchk`, rename `LIBCxyz.dll.normal` to `LIBCxyz.dll` and reboot. 92 92 93 Note that while technically you could copy `LIBCxyz.logchk` to a separate directory, rename it to `LIBCxyz.dll` there and then set BEGINLIBPATH=<DIR> and LIBPATHSTRICT=T in the environment to have this version of LIBC used for your process without rebooting, this will not work well. Doing so will lead to having two **different** LIBC copies in memory which don't cooperate because of the LIBC design that assumes there is only one active LIBC DLL at a time. In particular, having more than one DLL i tis known to make forked children crash with some weird errors (even if one manages to separate shared structures of different LIBC versions by using unique mutex and shared memory names).93 Note that while technically you could copy `LIBCxyz.logchk` to a separate directory, rename it to `LIBCxyz.dll` there and then set BEGINLIBPATH=<DIR> and LIBPATHSTRICT=T in the environment to have this version of LIBC used for your process without rebooting, this will not work well. Doing so will lead to having two **different** LIBC copies in memory which don't cooperate because of the LIBC design that assumes there is only one active LIBC DLL at a time. In particular, having more than one DLL in memory is known to make forked children crash with some weird errors (even if one manages to separate shared structures of different LIBC versions by using unique mutex and shared memory names).