This directive is only supported for targets that actually support arbitrarily named sections; on
targets, for example, it is not accepted, even with a standard
.section name [, "flags "] .section name [, subsection ]
If the optional argument is quoted, it is taken as flags to use for the section. Each flag is a single character. The following flags are recognized:
If no flags are specified, the default flags depend upon the section name. If the section name is not recognized, the default will be for the section to be loaded and writable. Note the
flags remove attributes from the section, rather than adding them, so if they are used on their own it will be as if no flags had been specified at all.
If the optional argument to the
directive is not quoted, it is taken as a subsection number (see Sub-Sections
This is one of the ELF section stack manipulation directives. The others are
.section name [, "flags "[, @type [,flag_specific_arguments ]]]
If the ‘
’ command-line option is provided, the name
argument may contain a substitution sequence. Only
is supported at the moment, and substitutes the current section name. For example:
.macro exception_code .section %S.exception [exception code here] .previous .endm .text [code] exception_code [...] .section .init [init code] exception_code [...]
invocations above would create the
sections respectively. This is useful e.g. to discriminate between anciliary sections that are tied to setup code to be discarded after use from anciliary sections that need to stay resident without having to define multiple
macros just for that purpose.
The optional flags argument is a quoted string which may contain any combination of the following characters:
Note - once a section's flags have been set they cannot be changed. There are a few exceptions to this rule however. Processor and application specific flags can be added to an already defined section. The
sections can have the allocate flag (
) set after they are initially defined, and the
section may have the executable (
) flag added.
The optional type argument may contain one of the following constants:
Many targets only support the first three section types. The type may be enclosed in double quotes if necessary.
Note on targets where the
character is the start of a comment (eg ARM) then another character is used instead. For example the ARM port uses the
Note - some sections, eg
are considered to be special and have fixed types. Any attempt to declare them with a different type will generate an error from the assembler.
symbol then the type
argument must be specified as well as an extra argument—entsize
.section name , "flags "M, @type , entsize
Sections with the
flag but not
flag must contain fixed size constants, each entsize
octets long. Sections with both
must contain zero terminated strings where each character is entsize
bytes long. The linker may remove duplicates within sections with the same name, same entity size and same flags. entsize
must be an absolute expression. For sections with both
, a string which is a suffix of a larger string is considered a duplicate. Thus
will be merged with
; A reference to the first
will be changed to a reference to
symbol then the type
argument must be present along with an additional field like this:
.section name , "flags "G, @type , GroupName [, linkage ]
The GroupName field specifies the name of the section group to which this particular section belongs. The optional linkage field can contain:
Note: if both the M and G flags are present then the fields for the Merge flag should come first, like this:
.section name , "flags "MG, @type , entsize , GroupName [, linkage ]
symbol then it may not also contain the
symbol and the GroupName
fields should not be present. Instead,
says to consider the section that's current before this directive. If that section used
, then the new section will use
with those same GroupName
fields implicitly. If not, then the
symbol has no effect.
If no flags are specified, the default flags depend upon the section name. If the section name is not recognized, the default will be for the section to have none of the above flags: it will not be allocated in memory, nor writable, nor executable. The section will contain data.
For ELF targets, the assembler supports another type of
directive for compatibility with the Solaris assembler:
.section "name "[, flags ...]
Note that the section name is quoted. There may be a sequence of comma separated flags:
This directive replaces the current section and subsection. See the contents of the gas testsuite directory
for some examples of how this directive and the other section stack directives work.