What does __ weak mean?
__weak. This keyword instructs the compiler to export symbols weakly. The __weak keyword can be applied to function and variable declarations, and to function definitions.
What does __ weak mean in C?
__weak function are methods that can be overwritten by user function with same name, used to define vector tables, and default handlers. Normal function writing (declaration and definition) are considered strong meaning that the function name cannot be re declared, you will get compiler/linker error.
What is __ Attribute__ weak ))?
The weak attribute causes the declaration to be emitted as a weak symbol rather than a global. This is primarily useful in defining library functions which can be overridden in user code, though it can also be used with non-function declarations.
What is #pragma weak?
1 #pragma weak name. In the form #pragma weak name , the directive makes name a weak symbol. The linker will not complain if it does not find a symbol definition for name . It also does not complain about multiple weak definitions of the symbol.
What does pragma weak mean?
#pragma weak symbol. This pragma declares symbol to be weak, as if the declaration had the attribute of the same name. The pragma may appear before or after the declaration of symbol , but must appear before either its first use or its definition. It is not an error for symbol to never be defined at all.
What is #pragma weak in C?
#pragma WEAK The WEAK pragma makes symbol a weak reference if it is a reference, or a weak definition, if it is a definition. The symbol can be a data or function variable. In effect, unresolved weak references do not cause linker errors and do not have any effect at run time.
What is the benefit of declaring a symbol as weak?
This behavior allows an executable to override standard library functions, such as malloc(3). When linking a binary executable, a weakly declared symbol does not need a definition.
What is Pragma weak?
Are multiple weak symbols with the same name allowed?
Uninitialized global variables get weak symbols. Rule 1: Multiple strong symbols (with same variable name) are not allowed.