Getting memory section information
- by Basilevs
Can somebody explain me how the following code works?
# if defined(__ELF__)
# define __SECTION_FLAGS ", \"aw\" , @progbits"
/* writable flag needed for ld ".[cd]tors" sections bug workaround) */
# elif defined(__COFF__)
# define __SECTION_FLAGS ", \"dr\""
/* untested, may be writable flag needed */
# endif
asm
(
".section .ctors" __SECTION_FLAGS "\n"
".globl __ctors_begin__\n"
"__ctors_begin__:\n"
".previous\n"
);
asm /* ld ".[cd]tors" sections bug workaround */
(
".section .ctors0" __SECTION_FLAGS "\n"
".globl __ctors0_begin__\n"
"__ctors0_begin__:\n"
".previous\n"
);
Similarly we are getting __ctors_end__ , __ctors0_end__ and destructors location is also obtained this way. After some ld bug workarounds all functions pointed by pointers from __ctors_begin__ to __ctors_end__ are executed. I don't know assembler and this code is impossible for me to interpret.
BTW: I know that invoking C++ contructors/destructors from C is not a task to be considered safe or easy.
