02-04-2013
Why this is needed in C goes to the heart of how C compiles and links.
Including <stdio.h> tells the compiler that "somewhere, there exists a function named fgets, which takes arguments of char *, int, and FILE *". So the compiler will assume that function exists, not complain about it when you use it, and get the arguments right without guessing. It doesn't need the function itself yet.
Later, when it links your program, it assembles everything from pieces and when it hunts for this name, it will find it in the standard libc library.
Once it's done piecing all these bits together, what it gives you is a program that can be loaded in memory, which is the bit you actually run.
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LEARN ABOUT SUSE
ccmakedep
ccmakedep(1) General Commands Manual ccmakedep(1)
NAME
ccmakedep - create dependencies in makefiles using a C compiler
SYNOPSIS
ccmakedep [ cpp-flags ] [ -wwidth ] [ -smagic-string ] [ -fmakefile ] [ -oobject-suffix ] [ -v ] [ -a ] [ -cccompiler ] [ -- options -- ]
sourcefile ...
DESCRIPTION
The ccmakedep program calls a C compiler to preprocess each sourcefile, and uses the output to construct makefile rules describing their
dependencies. These rules instruct make(1) on which object files must be recompiled when a dependency has changed.
By default, ccmakedep places its output in the file named makefile if it exists, otherwise Makefile. An alternate makefile may be speci-
fied with the -f option. It first searches the makefile for a line beginning with
# DO NOT DELETE
or one provided with the -s option, as a delimiter for the dependency output. If it finds it, it will delete everything following this up
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 makefile
and place the output after that.
EXAMPLE
Normally, ccmakedep will be used in a makefile target so that typing 'make depend' will bring the dependencies up to date for the makefile.
For example,
SRCS = file1.c file2.c ...
CFLAGS = -O -DHACK -I../foobar -xyz
depend:
ccmakedep -- $(CFLAGS) -- $(SRCS)
OPTIONS
The program will ignore any option that it does not understand, so you may use the same arguments that you would for cc(1), including -D
and -U options to define and undefine symbols and -I to set the include path.
-a Append the dependencies to the file instead of replacing existing dependencies.
-cccompiler
Use this compiler to generate dependencies.
-fmakefile
Filename. This allows you to specify an alternate makefile in which ccmakedep can place its output. Specifying "-" as the file
name (that is, -f-) sends the output to standard output instead of modifying an existing file.
-sstring
Starting string delimiter. This option permits you to specify a different string for ccmakedep to look for in the makefile. The
default is "# DO NOT DELETE".
-v Be verbose: display the C compiler command before running it.
-- options --
If ccmakedep encounters a double hyphen (--) in the argument list, then any unrecognized arguments following it will be silently
ignored. A second double hyphen terminates this special treatment. In this way, ccmakedep can be made to safely ignore esoteric
compiler arguments that might normally be found in a CFLAGS make macro (see the EXAMPLE section above). -D, -I, and -U options
appearing between the pair of double hyphens are still processed normally.
SEE ALSO
cc(1), make(1), makedepend(1), ccmakedep(1).
AUTHOR
ccmakedep was written by the X Consortium.
Colin Watson wrote this manual page, originally for the Debian Project, based partly on the manual page for makedepend(1).
X Version 11 imake 1.0.2 ccmakedep(1)