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Preface armclang Command-line Options Compiler-specific Keywords and Operators Compiler-specific Function, Variable, and Type Att Function attributes __attribute__((always_inline)) function attribute __attribute__((cmse_nonsecure_call)) function attr __attribute__((cmse_nonsecure_entry)) function att __attribute__((const)) function attribute __attribute__((constructor(priority))) function at __attribute__((format_arg(string-index))) function __attribute__((interrupt("type"))) function attrib __attribute__((malloc)) function attribute __attribute__((naked)) function attribute __attribute__((noinline)) function attribute __attribute__((nonnull)) function attribute __attribute__((noreturn)) function attribute __attribute__((nothrow)) function attribute __attribute__((pcs("calling_convention"))) functio __attribute__((pure)) function attribute __attribute__((section("name"))) function attribut __attribute__((unused)) function attribute __attribute__((used)) function attribute __attribute__((value_in_regs)) function attribute __attribute__((visibility("visibility_type"))) fun __attribute__((weak)) function attribute __attribute__((weakref("target"))) function attrib Type attributes __attribute__((aligned)) type attribute __attribute__((packed)) type attribute __attribute__((transparent_union)) type attribute Variable attributes __attribute__((alias)) variable attribute __attribute__((aligned)) variable attribute __attribute__((deprecated)) variable attribute __attribute__((packed)) variable attribute __attribute__((section("name"))) variable attribut __attribute__((unused)) variable attribute __attribute__((used)) variable attribute __attribute__((visibility("visibility_type"))) var __attribute__((weak)) variable attribute __attribute__((weakref("target"))) variable attrib Compiler-specific Intrinsics Compiler-specific Pragmas Other Compiler-specific Features Standard C Implementation Definition Standard C++ Implementation Definition armclang Integrated Assembler armclang Inline Assembler

__attribute__((visibility("visibility_type"))) variable attribute

3.36 __attribute__((visibility("visibility_type"))) variable attribute

This variable attribute affects the visibility of ELF symbols.

Syntax

__attribute__((visibility("visibility_type")))

Where visibility_type is one of the following:

default
Default visibility corresponds to external linkage.
hidden
The symbol is not placed into the dynamic symbol table, so no other executable or shared library can directly reference it. Indirect references are possible using function pointers.
protected
The symbol is placed into the dynamic symbol table, but references within the defining module bind to the local symbol. That is, another module cannot override the symbol.

Usage

This attribute overrides other settings that determine the visibility of symbols.

You can apply this attribute to functions and variables in C and C++. In C++, it can also be applied to class, struct, union, and enum types, and namespace declarations.

In the case of namespace declarations, the visibility attribute applies to all function and variable definitions.

Default

If you do not specify visibility, then the default type is default for extern declarations and hidden for everything else.

Example

int __attribute__((visibility("hidden"))) foo = 1;   // hidden in object file
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