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diff --git a/CCache/web/ccache-man.html b/CCache/web/ccache-man.html deleted file mode 100644 index b831e71da..000000000 --- a/CCache/web/ccache-man.html +++ /dev/null @@ -1,318 +0,0 @@ - - - - - -<html><head><title>ccache</title> - -<link rev="made" href="mailto:bugs@ccache.samba.org"> -</head> -<body> - -<hr> - -<h1>ccache</h1> -<h2>April 2002</h2> - - - -<h2>NAME</h2> - ccache - a fast compiler cache -<h2>SYNOPSIS</h2> - -<p>ccache [OPTION] -<p>ccache <compiler> [COMPILER OPTIONS] -<p><compiler> [COMPILER OPTIONS] -<p><h2>DESCRIPTION</h2> - -<p>ccache is a compiler cache. It speeds up re-compilation of C/C++ code -by caching previous compiles and detecting when the same compile is -being done again. -<p><h2>OPTIONS SUMMARY</h2> - -<p>Here is a summary of the options to ccache. -<p><pre> - --s show statistics summary --z zero statistics --c run a cache cleanup --C clear the cache completely --F <maxfiles> set maximum files in cache --M <maxsize> set maximum size of cache (use G, M or K) --h this help page --V print version number - -</pre> - -<p><h2>OPTIONS</h2> - -<p>These options only apply when you invoke ccache as "ccache". When -invoked as a compiler none of these options apply. In that case your -normal compiler options apply and you should refer to your compilers -documentation. -<p><dl> -<p></p><dt><strong><strong>-h</strong></strong><dd> Print a options summary page -<p><p></p><dt><strong><strong>-s</strong></strong><dd> Print the current statistics summary for the cache. The -statistics are stored spread across the subdirectories of the -cache. Using "ccache -s" adds up the statistics across all -subdirectories and prints the totals. -<p><p></p><dt><strong><strong>-z</strong></strong><dd> Zero the cache statistics. -<p><p></p><dt><strong><strong>-V</strong></strong><dd> Print the ccache version number -<p><p></p><dt><strong><strong>-c</strong></strong><dd> Clean the cache and re-calculate the cache file count and -size totals. Normally the -c option should not be necessary as ccache -keeps the cache below the specified limits at runtime and keeps -statistics up to date on each compile. This option is mostly useful -if you manually modify the cache contents or believe that the cache -size statistics may be inaccurate. -<p><p></p><dt><strong><strong>-C</strong></strong><dd> Clear the entire cache, removing all cached files. -<p><p></p><dt><strong><strong>-F maxfiles</strong></strong><dd> This sets the maximum number of files allowed in -the cache. The value is stored inside the cache directory and applies -to all future compiles. Due to the way the value is stored the actual -value used is always rounded down to the nearest multiple of 16. -<p><p></p><dt><strong><strong>-M maxsize</strong></strong><dd> This sets the maximum cache size. You can specify -a value in gigabytes, megabytes or kilobytes by appending a G, M or K -to the value. The default is gigabytes. The actual value stored is -rounded down to the nearest multiple of 16 kilobytes. -<p></dl> -<p><h2>INSTALLATION</h2> - -<p>There are two ways to use ccache. You can either prefix your compile -commands with "ccache" or you can create a symbolic link between -ccache and the names of your compilers. The first method is most -convenient if you just want to try out ccache or wish to use it for -some specific projects. The second method is most useful for when you -wish to use ccache for all your compiles. -<p>To install for usage by the first method just copy ccache to somewhere -in your path. -<p>To install for the second method do something like this: -<pre> - - cp ccache /usr/local/bin/ - ln -s /usr/local/bin/ccache /usr/local/bin/gcc - ln -s /usr/local/bin/ccache /usr/local/bin/g++ - ln -s /usr/local/bin/ccache /usr/local/bin/cc - -</pre> - -This will work as long as /usr/local/bin comes before the path to gcc -(which is usually in /usr/bin). After installing you may wish to run -"which gcc" to make sure that the correct link is being used. -<p>Note! Do not use a hard link, use a symbolic link. A hardlink will -cause "interesting" problems. -<p><h2>EXTRA OPTIONS</h2> - -<p>When run as a compiler front end ccache usually just takes the same -command line options as the compiler you are using. The only exception -to this is the option '--ccache-skip'. That option can be used to tell -ccache that the next option is definitely not a input filename, and -should be passed along to the compiler as-is. -<p>The reason this can be important is that ccache does need to parse the -command line and determine what is an input filename and what is a -compiler option, as it needs the input filename to determine the name -of the resulting object file (among other things). The heuristic -ccache uses in this parse is that any string on the command line that -exists as a file is treated as an input file name (usually a C -file). By using --ccache-skip you can force an option to not be -treated as an input file name and instead be passed along to the -compiler as a command line option. -<p><h2>ENVIRONMENT VARIABLES</h2> - -<p>ccache uses a number of environment variables to control operation. In -most cases you won't need any of these as the defaults will be fine. -<p><dl> -<p><p></p><dt><strong><strong>CCACHE_DIR</strong></strong><dd> the CCACHE_DIR environment variable specifies -where ccache will keep its cached compiler output. The default is -"$HOME/.ccache". -<p><p></p><dt><strong><strong>CCACHE_TEMPDIR</strong></strong><dd> the CCACHE_TEMPDIR environment variable specifies -where ccache will put temporary files. The default is the same as -CCACHE_DIR. Note that the CCACHE_TEMPDIR path must be on the same -filesystem as the CCACHE_DIR path, so that renames of files between -the two directories can work. -<p><p></p><dt><strong><strong>CCACHE_LOGFILE</strong></strong><dd> If you set the CCACHE_LOGFILE environment -variable then ccache will write some log information on cache hits -and misses in that file. This is useful for tracking down problems. -<p><p></p><dt><strong><strong>CCACHE_PATH</strong></strong><dd> You can optionally set CCACHE_PATH to a colon -separated path where ccache will look for the real compilers. If you -don't do this then ccache will look for the first executable matching -the compiler name in the normal PATH that isn't a symbolic link to -ccache itself. -<p><p></p><dt><strong><strong>CCACHE_CC</strong></strong><dd> You can optionally set CCACHE_CC to force the name -of the compiler to use. If you don't do this then ccache works it out -from the command line. -<p><p></p><dt><strong><strong>CCACHE_PREFIX</strong></strong><dd> This option adds a prefix to the command line -that ccache runs when invoking the compiler. Also see the section -below on using ccache with distcc. -<p><p></p><dt><strong><strong>CCACHE_DISABLE</strong></strong><dd> If you set the environment variable -CCACHE_DISABLE then ccache will just call the real compiler, -bypassing the cache completely. -<p><p></p><dt><strong><strong>CCACHE_READONLY</strong></strong><dd> the CCACHE_READONLY environment variable -tells ccache to attempt to use existing cached object files, but not -to try to add anything new to the cache. If you are using this because -your CCACHE_DIR is read-only, then you may find that you also need to -set CCACHE_TEMPDIR as otherwise ccache will fail to create the -temporary files. -<p><p></p><dt><strong><strong>CCACHE_CPP2</strong></strong><dd> If you set the environment variable CCACHE_CPP2 -then ccache will not use the optimisation of avoiding the 2nd call to -the pre-processor by compiling the pre-processed output that was used -for finding the hash in the case of a cache miss. This is primarily a -debugging option, although it is possible that some unusual compilers -will have problems with the intermediate filename extensions used in -this optimisation, in which case this option could allow ccache to be -used. -<p><p></p><dt><strong><strong>CCACHE_NOSTATS</strong></strong><dd> If you set the environment variable -CCACHE_NOSTATS then ccache will not update the statistics files on -each compile. -<p><p></p><dt><strong><strong>CCACHE_NLEVELS</strong></strong><dd> The environment variable CCACHE_NLEVELS allows -you to choose the number of levels of hash in the cache directory. The -default is 2. The minimum is 1 and the maximum is 8. -<p><p></p><dt><strong><strong>CCACHE_HARDLINK</strong></strong><dd> If you set the environment variable -CCACHE_HARDLINK then ccache will attempt to use hard links from the -cache directory when creating the compiler output rather than using a -file copy. Using hard links is faster, but can confuse programs like -'make' that rely on modification times. -<p><p></p><dt><strong><strong>CCACHE_RECACHE</strong></strong><dd> This forces ccache to not use any cached -results, even if it finds them. New results are still cached, but -existing cache entries are ignored. -<p><p></p><dt><strong><strong>CCACHE_UMASK</strong></strong><dd> This sets the umask for ccache and all child -processes (such as the compiler). This is mostly useful when you wish -to share your cache with other users. Note that this also affects the -file permissions set on the object files created from your -compilations. -<p><p></p><dt><strong><strong>CCACHE_HASHDIR</strong></strong><dd> This tells ccache to hash the current working -directory when calculating the hash that is used to distinguish two -compiles. This prevents a problem with the storage of the current -working directory in the debug info of a object file, which can lead -ccache to give a cached object file that has the working directory in -the debug info set incorrectly. This option is off by default as the -incorrect setting of this debug info rarely causes problems. If you -strike problems with gdb not using the correct directory then enable -this option. -<p><p></p><dt><strong><strong>CCACHE_UNIFY</strong></strong><dd> If you set the environment variable CCACHE_UNIFY -then ccache will use the C/C++ unifier when hashing the pre-processor -output if -g is not used in the compile. The unifier is slower than a -normal hash, so setting this environment variable loses a little bit -of speed, but it means that ccache can take advantage of not -recompiling when the changes to the source code consist of -reformatting only. Note that using CCACHE_UNIFY changes the hash, so -cached compiles with CCACHE_UNIFY set cannot be used when -CCACHE_UNIFY is not set and vice versa. The reason the unifier is off -by default is that it can give incorrect line number information in -compiler warning messages. -<p><p></p><dt><strong><strong>CCACHE_EXTENSION</strong></strong><dd> Normally ccache tries to automatically -determine the extension to use for intermediate C pre-processor files -based on the type of file being compiled. Unfortunately this sometimes -doesn't work, for example when using the aCC compiler on HP-UX. On -systems like this you can use the CCACHE_EXTENSION option to override -the default. On HP-UX set this environment variable to "i" if you use -the aCC compiler. -<p></dl> -<p><h2>CACHE SIZE MANAGEMENT</h2> - -<p>By default ccache has a one gigabyte limit on the cache size and no -maximum number of files. You can set a different limit using the -"ccache -M" and "ccache -F" options, which set the size and number of -files limits. -<p>When these limits are reached ccache will reduce the cache to 20% -below the numbers you specified in order to avoid doing the cache -clean operation too often. -<p><h2>HOW IT WORKS</h2> - -<p>The basic idea is to detect when you are compiling exactly the same -code a 2nd time and use the previously compiled output. You detect -that it is the same code by forming a hash of: -<p><ul> - <li > the pre-processor output from running the compiler with -E - <li > the command line options - <li > the real compilers size and modification time - <li > any stderr output generated by the compiler -</ul> -<p>These are hashed using md4 (a strong hash) and a cache file is formed -based on that hash result. When the same compilation is done a second -time ccache is able to supply the correct compiler output (including -all warnings etc) from the cache. -<p>ccache has been carefully written to always produce exactly the same -compiler output that you would get without the cache. If you ever -discover a case where ccache changes the output of your compiler then -please let me know. -<p><h2>USING CCACHE WITH DISTCC</h2> - -<p>distcc is a very useful program for distributing compilation across a -range of compiler servers. It is often useful to combine distcc with -ccache, so that compiles that are done are sped up by distcc, but that -ccache avoids the compile completely where possible. -<p>To use distcc with ccache I recommend using the CCACHE_PREFIX -option. You just need to set the environment variable CCACHE_PREFIX to -'distcc' and ccache will prefix the command line used with the -compiler with the command 'distcc'. -<p><h2>SHARING A CACHE</h2> - -<p>A group of developers can increase the cache hit rate by sharing a -cache directory. The hard links however cause unwanted side effects, -as all links to a cached file share the file's modification timestamp. -This results in false dependencies to be triggered by timestamp-based -build systems whenever another user links to an existing -file. Typically, users will see that their libraries and binaries are -relinked without reason. To share a cache without side effects, the -following conditions need to be met: -<p><ul> - <li > Use the same <strong>CCACHE_DIR</strong> environment variable setting - <li > Set the <strong>CCACHE_NOLINK</strong> environment variable - <li > Make sure everyone sets the CCACHE_UMASK environment variable - to 002, this ensures that cached files are accessible to everyone in - the group. - <li > Make sure that all users have write permission in the entire - cache directory (and that you trust all users of the shared cache). - <li > Make sure that the setgid bit is set on all directories in the - cache. This tells the filesystem to inherit group ownership for new - directories. The command "chmod g+s `find $CCACHE_DIR -type d`" might - be useful for this. -</ul> -<p><h2>HISTORY</h2> - -<p>ccache was inspired by the compilercache shell script script written -by Erik Thiele and I would like to thank him for an excellent piece of -work. See -<a href="http://www.erikyyy.de/compilercache/">http://www.erikyyy.de/compilercache/</a> -for the Erik's scripts. -<p>I wrote ccache because I wanted to get a bit more speed out of a -compiler cache and I wanted to remove some of the limitations of the -shell-script version. -<p><h2>DIFFERENCES FROM COMPILERCACHE</h2> - -<p>The biggest differences between Erik's compilercache script and ccache -are: -<ul> -<li > ccache is written in C, which makes it a bit faster (calling out to - external programs is mostly what slowed down the scripts). -<li > ccache can automatically find the real compiler -<li > ccache keeps statistics on hits/misses -<li > ccache can do automatic cache management -<li > ccache can cache compiler output that includes warnings. In many - cases this gives ccache a much higher cache hit rate. -<li > ccache can handle a much wider ranger of compiler options -<li > ccache avoids a double call to cpp on a cache miss -</ul> -<p><h2>BUGS</h2> - -<p>When the cache is stored on an NFS filesystem, the filesystem must be -exported with the <strong>no_subtree_check</strong> option to make renames between -directories reliable. -<p><h2>CREDITS</h2> - -<p>Thanks to the following people for their contributions to ccache -<ul> - <li > Erik Thiele for the original compilercache script - <li > Luciano Rocha for the idea of compiling the pre-processor output - to avoid a 2nd cpp pass - <li > Paul Russell for many suggestions and the debian packaging -</ul> -<p><h2>AUTHOR</h2> - -<p>ccache was written by Andrew Tridgell -<a href="http://samba.org/~tridge/">http://samba.org/~tridge/</a> -<p>If you wish to report a problem or make a suggestion then please email -bugs@ccache.samba.org -<p>ccache is released under the GNU General Public License version 2 or -later. Please see the file COPYING for license details. -</body> -</html> |