Segmentation fault problem

odedbobi · 11-19-2008, 02:07 AM

hello people.
i have a problem with my .so .
i am dynamically loading and unloading my libtemp.so using the dlopen and dlclose functions.
my .so contains many global instances of many classes.
i can see that all my global constructors are called on load and all my destructors are called on unload.
everything seems fine.
but when my program ends, i get a segmentation fault error.
here is my main.cpp:

Code:

int main( int argc, char * argv[] )
{ 
if( argc != 2 ){
printf("usage [so name] \n");
return 0;
}
printf("Before Load\r\n");
void* pHandle = dlopen(argv[1]);
if( pHandle == NULL ){
printf("%s\r\n", dlerror());
}else{
printf("Load: Went fine\r\n");
if( dlclose(pHandle) ){
printf("UnLoad Went Ok\r\n");
}else{
printf("UnLoad Failed\r\n");
}
}
return 0;
}

the output will be:
Before Load
Load: Went fine
UnLoad Went Ok
Segmentation fault

when debugging, i can see that my main reached it's ending, but still i get the segmentation fault error.
what might caused the problem ?
is it some memory leak ?
one of my globals problems ?
i will appreciate any help, cause i am kind of lost here.
thanks

matsp · 11-19-2008, 03:36 AM

You are supposed to pass two parameters to dlopen - not doing so could cause all sorts of different problems.

Also, your destructors are called on dlclose(), so you if you are accessing memory that isn't valid from the destructors, it will cause a seg fault.

--
Mats

11-19-2008, 02:07 AM	#1
odedbobi Registered User Join Date: Nov 2008 Posts: 1	Segmentation fault problem hello people. i have a problem with my .so . i am dynamically loading and unloading my libtemp.so using the dlopen and dlclose functions. my .so contains many global instances of many classes. i can see that all my global constructors are called on load and all my destructors are called on unload. everything seems fine. but when my program ends, i get a segmentation fault error. here is my main.cpp: Code: int main( int argc, char * argv[] ) { if( argc != 2 ){ printf("usage [so name] \n"); return 0; } printf("Before Load\r\n"); void* pHandle = dlopen(argv[1]); if( pHandle == NULL ){ printf("%s\r\n", dlerror()); }else{ printf("Load: Went fine\r\n"); if( dlclose(pHandle) ){ printf("UnLoad Went Ok\r\n"); }else{ printf("UnLoad Failed\r\n"); } } return 0; } the output will be: Before Load Load: Went fine UnLoad Went Ok Segmentation fault when debugging, i can see that my main reached it's ending, but still i get the segmentation fault error. what might caused the problem ? is it some memory leak ? one of my globals problems ? i will appreciate any help, cause i am kind of lost here. thanks
odedbobi is offline

11-19-2008, 03:36 AM	#2
matsp Kernel hacker Join Date: Jul 2007 Location: Farncombe, Surrey, England Posts: 15,686	You are supposed to pass two parameters to dlopen - not doing so could cause all sorts of different problems. Also, your destructors are called on dlclose(), so you if you are accessing memory that isn't valid from the destructors, it will cause a seg fault. -- Mats __________________ Compilers can produce warnings - make the compiler programmers happy: Use them! Please don't PM me for help - and no, I don't do help over instant messengers.
matsp is offline

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