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win32_before_main update to holding the symbol with linker include option replacing dllexport

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Allen Webster 2024-04-24 16:28:39 -07:00
parent 0b6adfde1e
commit 9ddc06fc0a
3 changed files with 14 additions and 11 deletions
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7
win32_before_main/DETAILS.txt
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@ -23,8 +23,11 @@ anything.
However, in this example I show how we can still make it work. We have to However, in this example I show how we can still make it work. We have to
make sure the linker won't eliminate the global variable that we are trying to make sure the linker won't eliminate the global variable that we are trying to
place into the ".CRT$XCU" section. I achieve this by marking it as an export place into the ".CRT$XCU" section. We can tell the linker to keep a symbol with
symbol. Export symbols can't be eliminated even if they aren't used locally. /include:<symbol-name> and we can add this command to the linker via a pragma
comment:
__pragma(comment(linker,"/include:<symbol-name>"))
From what I've seen in testing, this works as desired, even with the /GL option. From what I've seen in testing, this works as desired, even with the /GL option.

10
win32_before_main/win32_before_main.c
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@ -7,7 +7,7 @@ static void run_before_main_func(void);
// set the before-main execution function pointer // set the before-main execution function pointer
__declspec(allocate(".CRT$XCU")) __declspec(allocate(".CRT$XCU"))
__declspec(dllexport) __pragma(comment(linker,"/include:run_before_main_ptr"))
void (*run_before_main_ptr)(void) = run_before_main_func; void (*run_before_main_ptr)(void) = run_before_main_func;
// define the "before main" function // define the "before main" function
@ -27,10 +27,10 @@ int main(){
#if 0 #if 0
// wrapped in a macro: // wrapped in a macro:
#define BEFORE_MAIN(n) static void n(void); \ #define BEFORE_MAIN(n) static void n(void); \
__declspec(allocate(".CRT$XCU")) \ __declspec(allocate(".CRT$XCU")) \
__declspec(dllexport) \ __pragma(comment(linker,"/include:" #n "__")) \
void (*n##__)(void) = n; \ void (*n##__)(void) = n; \
static void n(void) static void n(void)
BEFORE_MAIN(before_main_rule){ BEFORE_MAIN(before_main_rule){

8
xlist/base.h
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@ -33,10 +33,10 @@
# pragma section(".CRT$XCU", read) # pragma section(".CRT$XCU", read)
# define BEFORE_MAIN(n) static void n(void); \ #define BEFORE_MAIN(n) static void n(void); \
__declspec(allocate(".CRT$XCU")) \ __declspec(allocate(".CRT$XCU")) \
__declspec(dllexport) \ __pragma(comment(linker,"/include:" #n "__")) \
void (*n##__)(void) = n; \ void (*n##__)(void) = n; \
static void n(void) static void n(void)
#elif OS_LINUX #elif OS_LINUX