Compilation can involve up to four stages: preprocessing, compilation proper, assembly and linking, always in that order. The first three stages apply to an individual source file, and end by producing an object file; linking combines all the object files (those newly compiled, and those specified as input) into an executable file.
For any given input file, the file name suffix determines what kind of compilation is done:
libobjc.ato make an Objective-C program work.
.cxx, the last two letters must both be literally
.Crefers to a literal capital C.
See Options Controlling the Kind of Output, for more details of the handling of
Fortran input files.
You can specify the input language explicitly with the
-xoption. Possible values for language are:
c c-header cpp-output c++ c++-cpp-output objective-c objc-cpp-output assembler assembler-with-cpp ada f77 f77-cpp-input ratfor java treelang
-xhas not been used at all).
gccprogram will exit with the code of 1 if any phase of the compiler returns a non-success return code. If you specify
gccprogram will instead return with numerically highest error produced by any phase that returned an error indication.
If you only want some of the stages of compilation, you can use
-x (or filename suffixes) to tell
gcc where to start, and
one of the options
-E to say where
gcc is to stop. Note that some combinations (for example,
-x cpp-output -E) instruct
gcc to do nothing at all.
By default, the object file name for a source file is made by replacing
.s, etc., with
Unrecognized input files, not requiring compilation or assembly, are
By default, the assembler file name for a source file is made by
replacing the suffix
.i, etc., with
Input files that don't require compilation are ignored.
Input files which don't require preprocessing are ignored.
Since only one output file can be specified, it does not make sense to
-o when compiling more than one input file, unless you are
producing an executable file as output.
-o is not specified, the default is to put an executable file
a.out, the object file for
.o, its assembler file in
all preprocessed C source on standard output.
-vexcept the commands are not executed and all command arguments are quoted. This is useful for shell scripts to capture the driver-generated command lines.
gcc. If the
-voption is also specified then
--helpwill also be passed on to the various processes invoked by
gcc, so that they can display the command line options they accept. If the
-Woption is also specified then command line options which have no documentation associated with them will also be displayed.