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Pointer initialization causing program abend?
Hi,
Working on an MS C ver6 program I was getting this error:
run-time error R6001
- null pointer assignment
The program worked correctly, but I wanted a clean run so investigated it.
When I tracked down the pointer I hadn't initialized, I corrected the program but it is now abending with Btrieve status 3. Now this usually means the file is not open, but that is not the case here as I got no error from the Open statement. The Btrieve MicroKernel also returns this status code if the application passed an invalid position block for the file, or if the application passed a position block with a client ID other than the client ID used to open the file.
Hence I am wondering if the memory is being corrupted and thus affecting the position block??
Here are some bits 'n' pieces from the program...
some variables, etc.
#define BTI_DOS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <btrapi.h>
#include <btrconst.h>
#define B_GETFST 12
#define B_GETNX 6
#define EOF_ERR 9
#define B_GETEQ 5
struct i2aRec
{
char Ac_cc [2];
char Ac_c [1];
char Ac_mm [2];
char Ac_nnnn [6];
char Ac_ss [2];
char Nd_acct [7];
char Bs_cntry [3];
char Ac_type [2];
char Intappfreq [3];
char Intbasedys [3];
char Matchlnact [13];
char Dt_ac_opnd [6];
char Line4 [6]; /* unpacked */
char SgnRept_bal[1];
char Rept_bal [14];
char Res [1];
char Ucntry [5];
char Bnsindust [5];
char UserICRS [6];
char Crintrt [9];
char Drintrt [9];
char Matur_dat [6];
char Locindu [5];
};
char *convData ; /* pointer to report balance output buffer */
char *datePtr ; /* pointer to maturity date output buffer */
char convTab[] = { 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
int GLD_BUF_LEN;
int CRD_BUF_LEN;
int CUB_BUF_LEN;
int CCY_BUF_LEN;
int I1A_BUF_LEN;
int BNS_BUF_LEN;
int OUT_BUF_LEN;
struct GLDRec GLD_REC_BUF, *pi;
struct crdRec CRD_REC_BUF, *pj;
struct cubRec CUB_REC_BUF, *pk;
struct ICRSEX1A I1A_REC_BUF, *pl;
struct i2aRec OUT_BUF, *po;
struct ccyRec CCY_REC_BUF, *pq;
struct bnsRec BNS_REC_BUF, *pp;
char GLD_POS_BLK[128];
char CRD_POS_BLK[128];
char CUB_POS_BLK[128];
char CCY_POS_BLK[128];
char BNS_POS_BLK[128];
char I1A_POS_BLK[128];
char OUT_POS_BLK[128];
char GLD_KEY_BUF[2];
char CRD_KEY_BUF[2];
char CRD_KEY_VALUE[6], *crdkey;
char CUB_KEY_BUF[2];
char CUB_KEY_VALUE[6], *cubkey;
char CCY_KEY_BUF[2];
char BNS_KEY_BUF[2];
char I1A_KEY_BUF[2];
char OUT_KEY_BUF[2];
char CCY_TABLE[60]= "";
char BNS_TAB[60]= "";
char I1A_NAME[60]= "";
char GLD_NAME[60]= "";
char CRD_NAME[60]= "";
char CUB_NAME[60]= "";
char OUT_NAME[60]="";
char txt_file[60]="";
char GL_MEMO[5];
char GL_ACCT[8];
int STATUS, cStatus, ck;
main ()
{
pi = &GLD_REC_BUF;
pj = &CRD_REC_BUF;
pk = &CUB_REC_BUF;
pl = &I1A_REC_BUF;
po = &OUT_BUF;
pp = &BNS_REC_BUF;
pq = &CCY_REC_BUF;
OUT_POS_BLK is the position block in question.
While loop
/* Read first GL record */
STATUS = BTRV (B_GETFST, GLD_POS_BLK, &GLD_REC_BUF, &GLD_BUF_LEN, GLD_KEY_BUF, 0);
count = 0;
readcount = 0;
while (STATUS != EOF_ERR) /* start of main while loop */
{
passflag = 0;
if (pi->GLDstatus == '@')
if (strncmp(GL_ACCT,"_____",5) != 0)
if (strncmp(GL_ACCT," ",5) != 0)
if (strncmp(GL_ACCT,"",5) != 0)
if (strncmp(pi->GLDAc_c,"3",1) <= 0)
if (strncmp(pi->GLDAc_type,"10",2) >= 0)
if (strncmp(pi->GLDAc_type,"99",2) <= 0)
if (strncmp(pi->GLDRept_bal,"00000000000000",14) != 0)
if (strncmp(pi->GLDRept_bal,"0000000000000P",14) != 0)
{
passflag = 1;
}
if ( passflag == 0 )
{
goto getnxt;
}
/* <snip> */
while (cStatus != EOF_ERR) /* start of a minor while loop */
{
if (cStatus != 0)
{
emessage("Reading","ICRSEX1A.BTR",cStatus);
exit(2);
}
if (strncmp(pl->ICAcCC, pi->GLDAc_cc, 2) == 0)
if (strncmp(pl->ICAcCX, pi->GLDAc_c, 1) == 0)
if (strncmp(pl->ICAcMM, pi->GLDAc_mm, 2) == 0)
if (strncmp(pl->ICAcno, pi->GLDAc_nnnn, 6) == 0)
if (strncmp(pl->ICAcSS, pi->GLDAc_ss, 2) == 0)
{
memcpy (po->Crintrt, pl->ICCrInt, 9);
memcpy (po->Drintrt, pl->ICDrInt, 9);
/* Convert BM date format to regular date format */
datePtr = (char *) pl->ICMatDt ;
/* THIS NEXT LINE CAUSES THE PROBLEM */
convData = (char *) pl->ICMatDt ;
/* copy converted date to output buffer */
strncpy (po->Matur_dat,
dateToString (datePtr, convData), 6);
cStatus = EOF_ERR;
}
if (cStatus != EOF_ERR)
{
cStatus = BTRV (B_GETNX, I1A_POS_BLK, &I1A_REC_BUF, &I1A_BUF_LEN, I1A_KEY_BUF, 0);
}
} /* end of the minor while loop */
/* <snip> */
/* ERROR WRITING ON FOLLOWING INSERT... */
/* Write ICRS record */
STATUS = BTRV (B_INSERT, OUT_POS_BLK, &OUT_BUF, &OUT_BUF_LEN, OUT_KEY_BUF, 0);
if (STATUS != 0)
{
emessage("Writing","ICRSEX2A.BTR",STATUS);
exit(2);
}
++count;
if ( count % 10 == 0 )
{
printf (" \r");
printf ("%d record(s) being written. \r", count);
}
getnxt:
/* Read next GL record */
STATUS = BTRV (B_GETNX, GLD_POS_BLK, &GLD_REC_BUF, &GLD_BUF_LEN, GLD_KEY_BUF, 0);
} /* end of main while loop */
printf ("%d record(s) written. \n", count);
DateToString subroutine
char *dateToString (char *inpData, char *outData)
{
int k = 0;
int l = 0;
char tempStr [1];
char *sDtePtr; /* pointer to data buffer */
sDtePtr = outData; /* assign pointer to output buffer */
strcpy (sDtePtr, inpData); /* copy input data to working buffer */
for (l = 0; l < 2; l++)
{
sDtePtr += l; /* mover pointer to second position */
for (k = 0 ; k < 11 ; k++)
{
/* check last byte of the string for 'PQRSTUVWXYZ' */
if (memcmp (sDtePtr, &convTab[k], 1) == 0 )
{
itoa (k, tempStr, 10); /* convert numeral to ASCII */
memcpy (sDtePtr, tempStr, 1); /* replace with ASCII */
}
}
}
sDtePtr -= 2; /* move pointer to the front */
return (outData);
}
If I remove the line
convData = (char *) pl->ICMatDt ;
then it works but gives me the null pointer run time error.
Any ideas why this is happening? Thanks... |
12-Dec-2006, 10:36
Meeting the local Iraqis by crystalattice
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