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These options are defined for all architectures running the Darwin operating system.
FSF GCC on Darwin does not create “fat” object files; it creates
an object file for the single architecture that GCC was built to
target. Apple’s GCC on Darwin does create “fat” files if multiple
-arch
options are used; it does so by running the compiler or
linker multiple times and joining the results together with
lipo
.
The subtype of the file created (like ‘ppc7400
’ or ‘ppc970
’ or
‘i686
’) is determined by the flags that specify the ISA
that GCC is targeting, like -mcpu
or -march
. The
-force_cpusubtype_ALL
option can be used to override this.
The Darwin tools vary in their behavior when presented with an ISA
mismatch. The assembler, as
, only permits instructions to
be used that are valid for the subtype of the file it is generating,
so you cannot put 64-bit instructions in a ‘ppc750
’ object file.
The linker for shared libraries, /usr/bin/libtool
, fails
and prints an error if asked to create a shared library with a less
restrictive subtype than its input files (for instance, trying to put
a ‘ppc970
’ object file in a ‘ppc7400
’ library). The linker
for executables, ld
, quietly gives the executable the most
restrictive subtype of any of its input files.
-Fdir
Add the framework directory dir
to the head of the list of
directories to be searched for header files. These directories are
interleaved with those specified by -I
options and are
scanned in a left-to-right order.
A framework directory is a directory with frameworks in it. A
framework is a directory with a Headers
and/or
PrivateHeaders
directory contained directly in it that ends
in .framework
. The name of a framework is the name of this
directory excluding the .framework
. Headers associated with
the framework are found in one of those two directories, with
Headers
being searched first. A subframework is a framework
directory that is in a framework’s Frameworks
directory.
Includes of subframework headers can only appear in a header of a
framework that contains the subframework, or in a sibling subframework
header. Two subframeworks are siblings if they occur in the same
framework. A subframework should not have the same name as a
framework; a warning is issued if this is violated. Currently a
subframework cannot have subframeworks; in the future, the mechanism
may be extended to support this. The standard frameworks can be found
in /System/Library/Frameworks
and
/Library/Frameworks
. An example include looks like
#include <Framework/header.h>
, where Framework
denotes
the name of the framework and header.h
is found in the
PrivateHeaders
or Headers
directory.
-iframeworkdir
Like -F
except the directory is a treated as a system
directory. The main difference between this -iframework
and
-F
is that with -iframework
the compiler does not
warn about constructs contained within header files found via
dir
. This option is valid only for the C family of languages.
-gused
Emit debugging information for symbols that are used. For stabs
debugging format, this enables -feliminate-unused-debug-symbols
.
This is by default ON.
-gfull
Emit debugging information for all symbols and types.
-mmacosx-version-min=version
The earliest version of MacOS X that this executable will run on
is version
. Typical values of version
include 10.1
,
10.2
, and 10.3.9
.
If the compiler was built to use the system’s headers by default, then the default for this option is the system version on which the compiler is running, otherwise the default is to make choices that are compatible with as many systems and code bases as possible.
-mkernel
Enable kernel development mode. The -mkernel
option sets
-static
, -fno-common
, -fno-use-cxa-atexit
,
-fno-exceptions
, -fno-non-call-exceptions
,
-fapple-kext
, -fno-weak
and -fno-rtti
where
applicable. This mode also sets -mno-altivec
,
-msoft-float
, -fno-builtin
and
-mlong-branch
for PowerPC targets.
-mone-byte-bool
Override the defaults for bool
so that sizeof(bool)==1
.
By default sizeof(bool)
is 4
when compiling for
Darwin/PowerPC and 1
when compiling for Darwin/x86, so this
option has no effect on x86.
Warning: The -mone-byte-bool
switch causes GCC
to generate code that is not binary compatible with code generated
without that switch. Using this switch may require recompiling all
other modules in a program, including system libraries. Use this
switch to conform to a non-default data model.
-mfix-and-continue
-ffix-and-continue
-findirect-data
Generate code suitable for fast turnaround development, such as to
allow GDB to dynamically load .o
files into already-running
programs. -findirect-data
and -ffix-and-continue
are provided for backwards compatibility.
-all_load
Loads all members of static archive libraries. See man ld(1) for more information.
-arch_errors_fatal
Cause the errors having to do with files that have the wrong architecture to be fatal.
-bind_at_load
Causes the output file to be marked such that the dynamic linker will bind all undefined references when the file is loaded or launched.
-bundle
Produce a Mach-o bundle format file. See man ld(1) for more information.
-bundle_loader executable
This option specifies the executable
that will load the build
output file being linked. See man ld(1) for more information.
-dynamiclib
When passed this option, GCC produces a dynamic library instead of
an executable when linking, using the Darwin libtool
command.
-force_cpusubtype_ALL
This causes GCC’s output file to have the ‘ALL
’ subtype, instead of
one controlled by the -mcpu
or -march
option.
-allowable_client client_name
-client_name
-compatibility_version
-current_version
-dead_strip
-dependency-file
-dylib_file
-dylinker_install_name
-dynamic
-exported_symbols_list
-filelist
-flat_namespace
-force_flat_namespace
-headerpad_max_install_names
-image_base
-init
-install_name
-keep_private_externs
-multi_module
-multiply_defined
-multiply_defined_unused
-noall_load
-no_dead_strip_inits_and_terms
-nofixprebinding
-nomultidefs
-noprebind
-noseglinkedit
-pagezero_size
-prebind
-prebind_all_twolevel_modules
-private_bundle
-read_only_relocs
-sectalign
-sectobjectsymbols
-whyload
-seg1addr
-sectcreate
-sectobjectsymbols
-sectorder
-segaddr
-segs_read_only_addr
-segs_read_write_addr
-seg_addr_table
-seg_addr_table_filename
-seglinkedit
-segprot
-segs_read_only_addr
-segs_read_write_addr
-single_module
-static
-sub_library
-sub_umbrella
-twolevel_namespace
-umbrella
-undefined
-unexported_symbols_list
-weak_reference_mismatches
-whatsloaded
These options are passed to the Darwin linker. The Darwin linker man page describes them in detail.
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