What is the use of pragma code section and data section?

Question

What exactly will happen to the data segment and text segment if I use the below two lines in my c source code file?

#pragma CODE_SECTION(func1, "Sec1")
#pragma DATA_SECTION(globalvar1, "Sec2")

Answer 1

Source (contains examples): https://web.archive.org/web/20080803190119/http://hi.baidu.com/jevidyang/blog/item/6d4dc436d87e3a300b55a918.html

Note: #pragma is compiler specific, so syntax may vary for your compiler.

The DATA_SECTION pragma allocates space for the symbol in a section called section name. The syntax for the pragma in C could be:

#pragma DATA_SECTION (symbol, "section name");

The syntax for the pragma in C++ could be:

#pragma DATA_SECTION ("section name");

The DATA_SECTION pragma is useful if you have data objects that you want to link into an area separate from the .bss section.

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The CODE_SECTION pragma allocates space for the func in a section named section name. The CODE_SECTION pragma is useful if you have code objects that you want to link into an area separate from the .text section. The syntax of the pragma in C could be:

#pragma CODE_SECTION (func, "section name")

The syntax of the pragma in C++ could be:

#pragma CODE_SECTION ("section name")

Answer 2

#pragma means "here follows something implementation-defined unique to this compiler". So what will happen depends on the compiler you are using. If the compiler doesn't support this specific pragma, the whole thing will be ignored.

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In this case it is fairly obvious, however.

#pragma CODE_SECTION(func1, "Sec1") means: "func1 should be in program memory, in the memory area called Sec1". Sec1 will be a read-only memory location where the actual code of func1 will be allocated.

#pragma DATA_SECTION(globalvar1, "Sec2") means: "globalvar1 should be in data memory, in the memory area called Sec2". Sec2 will be a read/write location where the variable globalvar1 will be allocated.