3.33 __attribute__((section("name"))) variable attribute

The section attribute specifies that a variable must be placed in a particular data section.

Normally, the Arm® compiler places the data it generates in sections like .data and .bss. However, you might require additional data sections or you might want a variable to appear in a special section, for example, to map to special hardware.

If you use the section attribute, read-only variables are placed in RO data sections, writable variables are placed in RW data sections.

To place ZI data in a named section, the section must start with the prefix .bss.. Non-ZI data cannot be placed in a section named .bss.

Example

/* in RO section */
const int descriptor[3] __attribute__((section ("descr"))) = { 1,2,3 };
/* in RW section */
long long rw_initialized[10] __attribute__((section ("INITIALIZED_RW"))) = {5};
/* in RW section */
long long rw[10] __attribute__((section ("RW")));
/* in ZI section */
int my_zi __attribute__((section (".bss.my_zi_section")));

Note:

Section names must be unique. You must not use the same section name for different section types. If you use the same section name for different section types, then the compiler merges the sections into one and gives the section the type of whichever function or variable is first allocated to that section.
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