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MAKEDEPEND(1) General Commands Manual MAKEDEPEND(1) NAME makedepend - create dependencies in makefiles SYNOPSIS makedepend [ -Dname=def ] [ -Dname ] [ -Iincludedir ] [ -Yincludedir ] [ -a ] [ -fmakefile ] [ -include file ] [ -oobjsuffix ] [ -pobjprefix ] [ -sstring ] [ -wwidth ] [ -v ] [ -m ] [ -- otheroptions -- ] sourcefile ... DESCRIPTION The makedepend program reads each sourcefile in sequence and parses it like a C-preprocessor, processing all #include, #define, #undef, #ifdef, #ifndef, #endif, #if, #elif and #else directives so that it can correctly tell which #include, directives would be used in a compila- tion. Any #include, directives can reference files having other #in- clude directives, and parsing will occur in these files as well. Every file that a sourcefile includes, directly or indirectly, is what makedepend calls a dependency. These dependencies are then written to a makefile in such a way that make(1) will know which object files must be recompiled when a dependency has changed. By default, makedepend places its output in the file named makefile if it exists, otherwise Makefile. An alternate makefile may be specified with the -f option. It first searches the makefile for the line # DO NOT DELETE THIS LINE -- make depend depends on it. or one provided with the -s option, as a delimiter for the dependency output. If it finds it, it will delete everything following this to the end of the makefile and put the output after this line. If it doesn't find it, the program will append the string to the end of the makefile and place the output following that. For each sourcefile ap- pearing on the command line, makedepend puts lines in the makefile of the form sourcefile.o: dfile ... Where sourcefile.o is the name from the command line with its suffix replaced with ``.o'', and dfile is a dependency discovered in a #in- clude directive while parsing sourcefile or one of the files it in- cluded. EXAMPLE Normally, makedepend will be used in a makefile target so that typing ``make depend'' will bring the dependencies up to date for the make- file. For example, SRCS = file1.c file2.c ... CFLAGS = -O -DHACK -I../foobar -xyz depend: makedepend -- $(CFLAGS) -- $(SRCS) OPTIONS The program will ignore any option that it does not understand so that you may use the same arguments that you would for cc(1). -Dname=def or -Dname Define. This places a definition for name in makedepend's symbol table. Without =def the symbol becomes defined as ``1''. -Iincludedir Include directory. This option tells makedepend to prepend in- cludedir to its list of directories to search when it encounters a #include directive. By default, makedepend only searches the standard include directories (usually /usr/include and possibly a compiler-dependent directory). -Yincludedir Replace all of the standard include directories with the single specified include directory; you can omit the includedir to simply prevent searching the standard include directories. -a Append the dependencies to the end of the file instead of replac- ing them. -fmakefile Filename. This allows you to specify an alternate makefile in which makedepend can place its output. Specifying ``-'' as the file name (i.e., -f-) sends the output to standard output instead of modifying an existing file. -include file Process file as input, and include all the resulting output before processing the regular input file. This has the same affect as if the specified file is an include statement that appears before the very first line of the regular input file. -oobjsuffix Object file suffix. Some systems may have object files whose suf- fix is something other than ``.o''. This option allows you to specify another suffix, such as ``.b'' with -o.b or ``:obj'' with -o:obj and so forth. -pobjprefix Object file prefix. The prefix is prepended to the name of the object file. This is usually used to designate a different direc- tory for the object file. The default is the empty string. -sstring Starting string delimiter. This option permits you to specify a different string for makedepend to look for in the makefile. -wwidth Line width. Normally, makedepend will ensure that every output line that it writes will be no wider than 78 characters for the sake of readability. This option enables you to change this width. -v Verbose operation. This option causes makedepend to emit the list of files included by each input file. -m Warn about multiple inclusion. This option causes makedepend to produce a warning if any input file includes another file more than once. In previous versions of makedepend this was the de- fault behavior; the default has been changed to better match the behavior of the C compiler, which does not consider multiple in- clusion to be an error. This option is provided for backward com- patibility, and to aid in debugging problems related to multiple inclusion. -- options -- If makedepend encounters a double hyphen (--) in the argument list, then any unrecognized argument following it will be silently ignored; a second double hyphen terminates this special treatment. In this way, makedepend can be made to safely ignore esoteric com- piler arguments that might normally be found in a CFLAGS make macro (see the EXAMPLE section above). All options that makede- pend recognizes and appear between the pair of double hyphens are processed normally. ALGORITHM The approach used in this program enables it to run an order of magni- tude faster than any other ``dependency generator'' I have ever seen. Central to this performance are two assumptions: that all files com- piled by a single makefile will be compiled with roughly the same -I and -D options; and that most files in a single directory will include largely the same files. Given these assumptions, makedepend expects to be called once for each makefile, with all source files that are maintained by the makefile ap- pearing on the command line. It parses each source and include file exactly once, maintaining an internal symbol table for each. Thus, the first file on the command line will take an amount of time proportional to the amount of time that a normal C preprocessor takes. But on sub- sequent files, if it encounters an include file that it has already parsed, it does not parse it again. For example, imagine you are compiling two files, file1.c and file2.c, they each include the header file header.h, and the file header.h in turn includes the files def1.h and def2.h. When you run the command makedepend file1.c file2.c makedepend will parse file1.c and consequently, header.h and then def1.h and def2.h. It then decides that the dependencies for this file are file1.o: header.h def1.h def2.h But when the program parses file2.c and discovers that it, too, in- cludes header.h, it does not parse the file, but simply adds header.h, def1.h and def2.h to the list of dependencies for file2.o. SEE ALSO cc(1), make(1) BUGS makedepend parses, but does not currently evaluate, the SVR4 #predi- cate(token-list) preprocessor expression; such expressions are simply assumed to be true. This may cause the wrong #include directives to be evaluated. Imagine you are parsing two files, say file1.c and file2.c, each in- cludes the file def.h. The list of files that def.h includes might truly be different when def.h is included by file1.c than when it is included by file2.c. But once makedepend arrives at a list of depen- dencies for a file, it is cast in concrete. AUTHOR Todd Brunhoff, Tektronix, Inc. and MIT Project Athena 4th Berkeley Distribution makedepend 1.0.9 MAKEDEPEND(1)
NAME | SYNOPSIS | DESCRIPTION | EXAMPLE | OPTIONS | ALGORITHM | SEE ALSO | BUGS | AUTHOR
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