Running program through Visual Studio causes it to fail? - c++

Question

I have a problem with a program that I'm writing. It is a command line parser that parses bencode (used in torrent files). The program accepts a filename as it's command line. When I build and run the program in Microsoft Visual Studio 10.0 using the debugging Commmand Line arguments setting to input a command line the program tells me that it failed parsing.
If I open a command prompt and run the program from the command prompt with the same command line, the program works perfectly! What's going on? Is this a common problem with Visual Studio?
I used the debugger in Visual Studio to trace where the program fails and it appears that a call to the stat function ( http://msdn.microsoft.com/en-us/library/14h5k7ff.aspx ) used to get the length of the file returns an error in Visual Studio but works fine when run outside of Visual Studio.
The Code uses a Bencode parser which can be found here: http://funzix.git.sourceforge.net/git/gitweb.cgi?p=funzix/funzix;a=blob;f=bencode/bencode.c
And here is the code for the program:
#include <stdio.h>
#include "../Parse/bencode.h"
int main(int argc, char *argv[]){
if(argc != 2){
printf("Usage: whirlwind filename\n");
return 1;
}
char *buf;
long long len;
be_node *n;
//read the torrent file into a buffer and store at &buf
buf = read_file(argv[1], &len);
if(!buf){
buf = argv[1];
len = strlen(argv[1]);
}
printf("Decoding: %s\n", argv[1]);
n = be_decoden(buf, len);
if(!n){
printf("Parsing failed!\n");
return 1;
}
if(n->type != BE_DICT){
printf("This file is not a valid Bencoded Dictionary.\n");
return 1;
}
int i;
char* keyName;
for(i = 0; i < 10; i++){
keyName = n->val.d[i].key;
if(keyName == "announce"){
printf("\n\n");
}
printf("%s\n", keyName);
if(keyName == "announce"){
printf("\n\n");
}
}
return 0;
}

Answer 1

If you pass a relative path from Visual Studio you should be sure that it resolves correctly when your app runs inside the IDE. This problem arises because, when debugging, the current directory is usually \bin\debug.
To be on the safe side put a full pathname or read the location of your file from a configuration file.