c# - Attempted to read write protected memory -

i have c++ dll exports method this:

extern "c" __declspec (dllexport) void conve(int type, const char* path, int b1, int b2, int b3, int b4, int b5) {     ffilelist file_list;      char temp_path[1024];      if(type == 1)      {         sprintf(temp_path,"%s*",path);         getfindfilelistwin(temp_path,".mrs",file_list);         file_list.recoveryzipe(b1, b2, b3, b4, b5);         file_list.convertnamemres2zip();     }     else if(type == 2)      {         sprintf(temp_path,"%s*",path);         getfindfilelistwin(temp_path,".zip",file_list);         file_list.convertzipe(b5, b4, b3, b2, b1);         file_list.convertnamezip2mres();     } } 

and i'm calling c# application this:

[dllimport("mrs.dll", charset = charset.ansi, callingconvention = callingconvention.cdecl)] public static extern void conve(int type, string path, int b1, int b2, int b3, int b4, int b5); 

but everytime run it, throws me error "attempt read or write protected memory indicating other memory corrupt"

as far read, there's wrong way i'm importing function in c#, don't know how solve it.

edit: default, there conv() same conve without 5 integers, , 1 works fine. made conve use file_list.recoveryzipe() when debugging, stacks me on method inside 1 called recvoerychare (i added code, can take it) , also, 1 base on recoverychar() works on conv().

recoverychar:

void recoverychar(char* pdata,int _size) {     if(!pdata) return;     byte b,bh,d;      for(int i=0;i<_size;i++) {         b = *pdata;         bh = b&0x07;         d = (bh<<5)|(b>>3);         *pdata = d ^ 0xff;         pdata++;     } }  

recvoerychare:

void recoverychare(char* pdata, int _size, int b1, int b2, int b3, int b4, int b5) {     if(!pdata) return;      byte b;      for(int i=0;i<_size;i++) {         b = *pdata;         b = (((((b >> b1) | (b << 5)) ^ b2) + b3) ^ b4) - b5;         *pdata = b;         pdata++;     } }  

last exception got when debugging c# app:

edit: after debugging again, stucks on here

recoverychare( _fileheaderreader , _fileheaderreadersize, b1, b2, b3, b4, b5 ); 

for reason, b1 value taking 0 always. , seems reason i'm getting protected memory error.

all did copy methods recoverychar() , convertchar() present , pass values parameters.

i explore things:

1. what platform on c++ , on c# side ? both 32-bits ? both 64-bits ? may have issue parameters transfer between 2 languages done wrong if have mix of integer length. anyway safest bet specify exact integer width using instance 'int32_t' instead of 'int'

2. some people suggest specifiying exact marshaller when converting c++ 'char*' c# 'string' using instance "marshalas(unmanagedtype.lpstr)] string path", please try this

3. finally add "printf-like" debugging code in c++ dump values @ various steps (including @ begining of call) debugging console. can use following function used printf outputs debuging console.

code sample debug output in c++:

inline void log_(const char *format, ...) {   va_list args;   va_start(args, format);    char buffer[1000];   vsprintf(buffer, format, args);   outputdebugstringa(buffer); }