This section describes variables that specify the programs to be used for applying patches and for computing the main difference regions (not the fine difference regions):
ediff-diff-program ¶ediff-diff3-programThese variables specify the programs to use to produce differences and do patching.
ediff-diff-options ¶ediff-diff3-optionsThese variables specify the options to pass to the above utilities.
In ediff-diff-options, it may be useful to specify options
such as ‘-w’ that ignore certain kinds of changes. However,
Ediff does not let you use the option ‘-c’, as it doesn’t recognize this
format yet. (If you alter this variable, it should be done via the
Customize interface instead of using setq directly.)
ediff-coding-system-for-read ¶This variable specifies the coding system to use when reading the output
that the programs diff3 and diff send to Emacs. The default
is raw-text, and this should work fine in Unix and in most
cases under Windows NT/95/98/2000. There are diff programs
for which the default option doesn’t work under Windows. In such cases,
raw-text-dos might work. If not, you will have to experiment with
other coding systems or use GNU diff.
ediff-patch-programThe program to use to apply patches. Since there are certain
incompatibilities between the different versions of the patch program, the
best way to stay out of trouble is to use a GNU-compatible version.
Otherwise, you may have to tune the values of the variables
ediff-patch-options, ediff-backup-specs, and
ediff-backup-extension as described below.
ediff-patch-optionsOptions to pass to ediff-patch-program.
Note: the -b and -z options should be specified in
ediff-backup-specs, not in ediff-patch-options.
It is recommended to pass the -f option to the patch program, so it won’t ask questions. However, some implementations don’t accept this option, in which case the default value of this variable should be changed.
ediff-backup-extensionBackup extension used by the patch program. Must be specified, even if
ediff-backup-specs is given.
ediff-backup-specsBackup directives to pass to the patch program. Ediff requires that the old version of the file (before applying the patch) is saved in a file named the-patch-file.extension. Usually extension is .orig, but this can be changed by the user, and may also be system-dependent. Therefore, Ediff needs to know the backup extension used by the patch program.
Some versions of the patch program let the user specify -b extension to specify a backup file name extension. Other versions only permit -b, which (usually) assumes the extension .orig. Yet others force you to use -zextension.
Both ediff-backup-extension and ediff-backup-specs must
be properly set. If your patch program takes the option -b,
but not -b extension, the variable
ediff-backup-extension must still be set so Ediff will know
which extension to use.
ediff-custom-diff-program ¶ediff-custom-diff-optionsBecause Ediff limits the options you may want to pass to the diff
program, it partially makes up for this drawback by letting you save the
output from diff in your preferred format, which is specified via
the above two variables.
The output generated by ediff-custom-diff-program (which doesn’t
even have to be a standard-style diff!) is not used by Ediff. It is
provided exclusively so that you can
refer to
it later, send it over email, etc. For instance, after reviewing the
differences, you may want to send context differences to a colleague.
Since Ediff ignores the ‘-c’ option in
ediff-diff-program, you would have to run diff -c separately
just to produce the list of differences. Fortunately,
ediff-custom-diff-program and ediff-custom-diff-options
eliminate this nuisance by keeping a copy of a difference list in the
desired format in a buffer that can be displayed via the command D.
ediff-patch-default-directory ¶Specifies the default directory to look for patches.