Exit code 3 (not my return value, looking for source)

Question

Greetings,

my program exits with the code 3. No error messages, no exceptions, and the exit is not initiated by my code.

The problem occurs when I am trying to read extremely long integer values from a text file (the text file is present and correctly opened, with successful prior reading).

I am using very large amounts of memory (in fact, I think that this might be the cause, as I am nearly sure I go over the 2GB per process memory limit). I am also using the GMP (or, rather, MPIR) library to multiply bignums. I am fairly sure that this is not a file I/O problem as I got the same error code on a previous program version that was fully in-memory.

System:
MS Visual Studio 2008
MS Windows Vista Home Premium x86
MPIR 2.1.0 rc2
4GB RAM

Where might this error code originate from?

EDIT: this is the procedure that exits with the code

void condenseBinSplitFile(const char *sourceFilename, int partCount){
//condense results file into final P and Q
std::string tempFilename;
std::string inputFilename(sourceFilename);
std::string outputFilename(BIN_SPLIT_FILENAME_DATA2);
mpz_class *P = new mpz_class(0);
mpz_class *Q = new mpz_class(0);
mpz_class *PP = new mpz_class(0);
mpz_class *QQ = new mpz_class(0);
FILE *sourceFile;
FILE *resultFile;

fpos_t oldPos;
int swapCount = 0;
while (partCount > 1){
    std::cout << partCount << std::endl;
    sourceFile = fopen(inputFilename.c_str(), "r");     
    resultFile = fopen(outputFilename.c_str(), "w");
    for (int i=0; i<partCount/2; i++){
        //Multiplication order:
        //Get Q, skip P
        //Get QQ, mul Q and QQ, print Q, delete Q
        //Jump back to P, get P
        //Mul P and QQ, delete QQ
        //Skip QQ, get PP
        //Mul P and PP, delete P and PP

        //Get Q, skip P
        mpz_inp_str(Q->get_mpz_t(), sourceFile, CALC_BASE);
        fgetpos(sourceFile, &oldPos);
        skipLine(sourceFile);
        skipLine(sourceFile);

        //Get QQ, mul Q and QQ, print Q, delete Q
        mpz_inp_str(QQ->get_mpz_t(), sourceFile, CALC_BASE);      
        (*Q) *= (*QQ);
        mpz_out_str(resultFile, CALC_BASE, Q->get_mpz_t());
        fputc('\n', resultFile);
        (*Q) = 0;

        //Jump back to P, get P
        fsetpos(sourceFile, &oldPos);
        mpz_inp_str(P->get_mpz_t(), sourceFile, CALC_BASE);

        //Mul P and QQ, delete QQ
        (*P) *= (*QQ);
        (*QQ) = 0;

        //Skip QQ, get PP
        skipLine(sourceFile);
        skipLine(sourceFile);
        mpz_inp_str(PP->get_mpz_t(), sourceFile, CALC_BASE); 
        //Mul P and PP, delete PP, print P, delete P             
        (*P) += (*PP);
        (*PP) = 0;
        mpz_out_str(resultFile, CALC_BASE, P->get_mpz_t());
        fputc('\n', resultFile);
        (*P) = 0;
    }
    partCount /= 2;

    fclose(sourceFile);
    fclose(resultFile);

    //swap filenames
    tempFilename = inputFilename;
    inputFilename = outputFilename;
    outputFilename = tempFilename;
    swapCount++;
}

delete P;
delete Q;
delete PP;
delete QQ;

remove(BIN_SPLIT_FILENAME_RESULTS);
if (swapCount%2 == 0)
    rename(sourceFilename, BIN_SPLIT_FILENAME_RESULTS);
else
    rename(BIN_SPLIT_FILENAME_DATA2, BIN_SPLIT_FILENAME_RESULTS);
}

EDIT2: completely in-memory version that also exits with 3

void binarySplitE(const ULONG first, const ULONG last, mpz_class *P, mpz_class *Q){
//P(first, last) = P(first, mid)*Q(mid, last) + P(mid, last)
//Q(first, last) = Q(first, mid)*Q(mid, last)
if (last - first == 1){
    calcP(P, first, last);
    calcQ(Q, first, last);
    return;
}

ULONG mid = (first+last)/2;
mpz_class *PP = new mpz_class(*P);
mpz_class *QQ = new mpz_class(*Q);
//Calculate P(first, mid) and Q(first, mid)
binarySplitE(first, mid, P, Q);
//Calculate P(mid, last) and Q(mid, last)
binarySplitE(mid, last, PP, QQ);

//P(first, last) == P(first, mid)
*P *= (*QQ);
//P(first, last) == P(first, mid)*Q(mid, last)
*P += (*PP);
//P(first, last) == P(first, mid)*Q(mid, last) + P(mid, last);

//Q(first, last) == Q(first, mid)
*Q *= (*QQ);
//Q(first, last) == Q(first, mid)*Q(mid, last)

delete PP;
delete QQ;
}

I am not exactly sure where the exit happens precisely, however, I have pasted the function responsible. It's problematic to trace it as this happens at the end of about 3-4 hrs of computation time. — nikaspran, Jun 06 '10 at 17:49
The error code points at file IO, according to [this](http://msdn.microsoft.com/en-us/library/ms681382%28v=VS.85%29.aspx). Could be indirect though; have you tried running this code on something [like valgrind](http://stackoverflow.com/questions/413477/is-there-a-good-valgrind-substitute-for-windows), could be that a FILE struct is getting clobbered by an out of bounds write, a danger with GMP. — academicRobot, Jun 06 '10 at 19:26
Unfortunately, I got the same exit code when I tried to run a completely in-memory implementation of the same process (I have posted code of that function). — nikaspran, Jun 06 '10 at 19:33
Sorry, my point was really the second part of my comment; have you tried checking for out of bounds memory reads/writes? These can often lead to delayed, very random seeming errors. (Not a segfault unless it accesses outside application memory, and since your using so much, most memory is in the application.) — academicRobot, Jun 06 '10 at 20:16

score 0 · Accepted Answer · answered Jun 13 '10 at 12:53

0

It appears this exit code was returned by MPIR(GMP) because it could not allocate a big amount of memory. It's a bit annoying that this was not in any of the documentation though.

answered Jun 13 '10 at 12:53

nikaspran

312
1
3
10

You could always check what http://www.opengroup.org/onlinepubs/000095399/functions/perror.html spits out in these cases. – Alexander Torstling Jun 13 '10 at 12:57

Exit code 3 (not my return value, looking for source)

1 Answers1