[英]Segmentation Fault using fscanf
我已經為一些基本的文本處理工作編寫了C語言代碼。首先是從文件中讀取,然后根據某些字符將其拆分。 但是,我在使用gcc進行編譯時遇到分段錯誤,當我使用gdb時,它輸出fscanf行導致分段錯誤。 我在StackOverflow上瀏覽了許多文章,但是沒有建議的解決方案解決了我的問題。 謝謝
產量
Number of Lines 9
LXI B
Segmentation fault
gdb輸出,原因為SIGSEGV
#0 0xb7eb0c5d in __isoc99_fscanf ()
from /lib/i386-linux-gnu/i686/cmov/libc.so.6
#1 0x08048af5 in setupTables () at simGen.c:132
#2 0x08048687 in main () at simGen.c:26
simGen.c
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<strings.h>
#include<ctype.h>
#include<malloc.h>
#define newlineCheck(t,flg){\
if(t == '\n'){\
flg=1;\
}}\
//GLOBAL VARS
char mnem[50][10],op1[50][5],op2[50][5];
FILE *fp;
void setupTables();
int compare(char *,char *);
int main(){
setupTables();
return 0;
}
int compare(char *a,char *b){
if(strcmp(a,b)){
return 0;
}else{
return 1;
}
}
void setupTables(){
char tempch = 'a';
int commapos = 0,spacepos = 0,digitFlag = 0,colonpos = 0,i = 0;
char instr[10];
int counter,num_lines = 1,line_counter = 1;
FILE* fp = fopen("asm.txt","r");
while(fscanf(fp,"%c",&tempch)!=EOF){
if(tempch == '\n'){
num_lines++;
}
}
printf("Number of Lines %d\n",num_lines);
rewind(fp);
do{
counter = 0;
spacepos = 0;
commapos = 0;
digitFlag = 0;
colonpos = 0;
do{
fscanf(fp,"%c",&tempch);// <- this line seems to be causing segmentation fault
instr[counter] = tempch;
if(isdigit(tempch))
digitFlag = 1;
if(tempch == ' ')
spacepos = counter;
if(tempch == ',')
commapos = counter;
if(tempch == ':')
colonpos = counter;
counter++;
}while(tempch != '\n');
instr[counter - 2] = '\0';
if(digitFlag == 0){
i = 0;
if(colonpos == 0){
do{
mnem[line_counter - 1][i] = instr[i];
i++;
}while(instr[i-1] != '\0');
}else{
do{
//mnem[line_counter - 1][i] = instr[i];
i++;
}while(instr[i-1] != ':');
int j = 0;
do{
mnem[line_counter - 1][j] = instr[i];
j++;
i++;
}while(instr[i-1] != '\0');
}
}else{
if(colonpos == 0){
if(commapos == 0){
for(i = 0;i <= spacepos;i++){
mnem[line_counter - 1][i] = instr[i];
}
mnem[line_counter - 1][spacepos] = '\0';
}else{
for(i = 0;i <= commapos;i++){
mnem[line_counter - 1][i] = instr[i];
}
mnem[line_counter - 1][commapos] = '\0';
}
}else{
int j = 0;
do{
//mnem[line_counter - 1][i] = instr[i];
j++;
}while(instr[j-1] != ':');
if(commapos == 0){
for(i = 0;i <= spacepos - j + 2;i++){
mnem[line_counter - 1][i] = instr[j];
j++;
}
mnem[line_counter - 1][spacepos] = '\0';
}else{
for(i = 0;i <= commapos - j + 3;i++){
mnem[line_counter - 1][i] = instr[j];
j++;
}
mnem[line_counter - 1][commapos] = '\0';
}
}
}
printf("%s\n",mnem[line_counter - 1]);
line_counter++;
}while(line_counter!=num_lines);
}
asm.txt
LXI B,501A
波爾:LDA 4150
標簽:MOV E,A
客:STAX 2130
MOV D,A
回路:MVI A,23
LXI H,76AC
HLT
您的問題是這條線。
char instr[10];
當它到達asm.txt
第三asm.txt
,即LABEL:MOV E,A
,您分配的空間不足。 我將空間增加到20,程序正常運行。
char instr[20];
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