When Do Globals Go In .Bss And .Data? Update Mới

In general, global variables go in either the .bss section or the .data section of a program’s memory.

The .bss section is used for uninitialized global variables and static variables. When a program is loaded into memory, the operating system sets aside a block of memory for the .bss section and initializes all the bytes to zero. This section is typically used for variables that don’t have an initial value specified in the program code.

The .data section is used for initialized global variables and static variables. This section is typically used for variables that have an initial value specified in the program code.

The decision to place a global variable in either the .bss or .data section is usually made by the compiler, based on whether or not the variable has an initial value specified in the program code. If a global variable is initialized, it will be placed in the .data section. If it is uninitialized, it will be placed in the .bss section.

It’s worth noting that different programming languages and compilers may have different rules for where global variables are placed in memory. Additionally, some programs may use custom memory allocation schemes that do not use the .bss or .data sections at all.

In most programming languages, global variables are typically stored in either the data segment or the bss (block started by symbol) segment of the program’s memory.

The data segment is used to store initialized global variables, which means that these variables have a predetermined value assigned to them when the program starts execution. In contrast, the bss segment is used to store uninitialized global variables, which means that these variables do not have a predetermined value assigned to them when the program starts execution.

Since uninitialized global variables are by definition set to zero, they can be stored in the bss segment, which is a portion of the data segment that contains all the variables initialized to zero or uninitialized.

So, to answer your question, yes, global variables can be stored in the bss segment. However, the specific location of global variables in memory can depend on the programming language, compiler, and operating system being used.

Global variables are stored in the data segment of a program’s memory because the data segment is specifically reserved for static variables that are initialized before the program starts executing.

When a program is loaded into memory, the operating system allocates different regions of memory to store different types of data. The data segment is one such region of memory that contains initialized static variables, such as global variables.

Because global variables are declared outside of any function, they are initialized before the program starts executing. As a result, they are stored in the data segment along with other static variables that are initialized before the program starts.

Storing global variables in the data segment has several advantages, including:

1. Efficient memory usage: Since global variables are stored in the data segment, the memory required for these variables is allocated only once at the start of the program. This results in efficient memory usage since the program does not need to allocate and deallocate memory for these variables repeatedly.

2. Easy access: Because global variables are stored in a single location, they can be easily accessed from anywhere in the program. This makes it easy to share data between different functions or modules.

3. Persistence: Global variables remain in memory throughout the lifetime of the program. This means that their values persist even if the function that created them has returned or if the program has ended.

In computer programming, the BSS (Block Started by Symbol) section is a portion of the memory that contains uninitialized global and static variables. When a program is loaded into memory, the BSS section is allocated a block of memory that is large enough to hold all of the uninitialized variables that are declared in the program.

The BSS section includes:

1. Uninitialized global variables: These are variables that are declared outside of any function and are not initialized to a specific value. They are assigned the default value of 0 by the compiler.

2. Uninitialized static variables: These are variables that are declared inside a function with the static keyword and are not initialized to a specific value. They are also assigned the default value of 0 by the compiler.

3. Uninitialized arrays: Arrays that are not initialized to a specific value are also stored in the BSS section. These can be either global or local.

4. Uninitialized pointers: Pointers that are not initialized to a specific value are also stored in the BSS section. These can be either global or local.

It’s worth noting that only uninitialized variables are stored in the BSS section. Initialized variables are stored in the data section of the program.