Red Hat ENTERPRISE LINUX 4 Manual page 122

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-freg-struct-return
Return
struct
structures than
-fpcc-struct-return
If you specify neither
whichever convention is standard for the target. If there is no standard convention, GCC defaults
to
-fpcc-struct-return
cases, we can choose the standard, and we chose the more efficient register return alternative.
Warning: code compiled with the
code compiled with the
application binary interface.
-fshort-enums
Allocate to an
enum
Specifically, the
Warning: the
-fshort-enums
with code generated without that switch. Use it to conform to a non-default application binary
interface.
-fshort-double
Use the same size for
Warning: the
-fshort-double
patible with code generated without that switch. Use it to conform to a non-default application
binary interface.
-fshort-wchar
Override the underlying type for
for the target. This option is useful for building programs to run under WINE.
Warning: the
-fshort-wchar
with code generated without that switch. Use it to conform to a non-default application binary
interface.
-fshared-data
Requests that the data and non-
private data. The distinction makes sense only on certain operating systems, where shared data
is shared between processes running the same program, while private data exists in one copy per
process.
-fno-common
In C, allocate even uninitialized global variables in the data section of the object file, rather
than generating them as common blocks. This has the effect that if the same variable is declared
(without
extern
only reason this might be useful is if you wish to verify that the program will work on other
systems which always work this way.
-fno-ident
Ignore the
#ident
-finhibit-size-directive
Don't output a
.size
tion is split in the middle, and the two halves are placed at locations far apart in memory. This
option is used when compiling
and values in registers when possible. This is more efficient for small
union
-fpcc-struct-return
, except on targets where GCC is the principal compiler. In those
-freg-struct-return
-fpcc-struct-return
type only as many bytes as it needs for the declared range of possible values.
type will be equivalent to the smallest integer type which has enough room.
enum
switch causes GCC to generate code that is not binary compatible
as for
double
switch causes GCC to generate code that is not binary com-
wchar_t
switch causes GCC to generate code that is not binary compatible
const
) in two different compilations, you will get an error when you link them. The
directive.
assembler directive, or anything else that would cause trouble if the func-
crtstuff.c
Chapter 4. GCC Command Options
.
nor
-freg-struct-return
switch. Use it to conform to a non-default
.
float
to be
short unsigned int
variables of this compilation be shared data rather than
; you should not need to use it for anything else.
, GCC defaults to
switch is not binary compatible with
instead of the default