2.1.2 Predefined User Sections

A section that can be manipulated by the section control directives is known as a user section. You can use the section control directives to change the user section in which code or data is generated. Table 2–3 lists some of the predefined user sections that can be named in the section control directives. For details and additional information, see Special Sections in Oracle Solaris 11.2 Linkers and Libraries Guide

Table 2-3  User Sections In Section Control Directives

Section Name Description .bss Section contains uninitialized read-write data. .comment Comment section. .data & .data1 Section contains initialized read-write data. .debug Section contains debugging information. .fini Section contains runtime finalization instructions. .init Section contains runtime initialization instructions. .rodata & .rodata1 Section contains read-only data. .text Section contains executable text. .line Section contains line # info for symbolic debugging. .note Section contains note information.

2.1.2.1 Creating an .init Section in an Object File

The .init sections contain codes that are to be executed before the the main program is executed. To create an .init section in an object file, use the assembler pseudo-ops shown in Example 2–1 .

Example 2-1  Creating an .init Section

.section ".init"

.align   4

<instructions>

At link time, the .init sections in a sequence of .o files are concatenated into an .init section in the linker output file. The code in the .init section are executed before the main program is executed.

Because the whole .init section is treated as a single function body, it is recommented that the only code added to these sections be in the following form:.

call routine_name nop

The called routine should be located in another section. This will prevent conflicting register and stack usage within the .init sections.

2.1.2.2 Creating a .fini Section in an Object File

.fini sections contain codes that are to be executed after the the main program is executed. To create an .fini section in an object file, use the assembler pseudo-ops shown in Example 2–2 .

Example 2-2  Creating an .fini Section

.section ".fini"

.align   4

<instructions>

At link time, the .fini sections in a sequence of .o files are concatenated into a .fini section in the linker output file. The codes in the .fini section are executed after the main program is executed.

Because the whole .fini section is treated as a single function body, it is recommended that the only code added to these section be in the following form:.

call routine_name nop

The called routine should be located in another section. This will prevent conflicting register and stack usage within the .fini sections.