CODEWITHSUNDEEP
c++clinuxfile
Amit Tomar
Amit Tomar

Reputation: 4858

EOF going into infinite loop

I am greping and awking some text from a file and writing it to another one.

When I am trying to open and read log_2 to do something, it works fine in case the grep returned some string.

But if grep itself dint return anything , my code is going into an infinite loop. I tried printing the character being read in the loop, it prints a ' ÿ ' infinitely.

system("egrep 'Security = |State = ' log.txt > log_1.txt");
system("awk -F ' Security = | State = { Interface=' '{print $2}' log_1.txt > log_2.txt ");

// The exact strings to be greped and awked are different. Cant write them here.    

FILE *pReadFile;
char cTemp;

pReadFile=fopen ( "log_2.txt" , "r+");

if (pReadFile==NULL )
{
    std::cout << ("Error opening Config file");
    fclose(pReadFile);
    return ;
}

cTemp = fgetc (pReadFile);

if(cTemp == EOF)    
return ; 


while( cTemp != EOF )
{
      // Do Something

      cTemp = fgetc (pReadFile);
}

Can someone explain ?

Just to add in case someone is having similar issue, this code works fine on Intel based Ubuntu systems, but Freescale ones with Ubuntu will cause a problem. So be careful, and always use int to be safe.

Upvotes: 0

Views: 231

Answers (1)

ouah
ouah

Reputation: 145839

EOF is an int not a char.

char cTemp;

should be:

int Temp;

See here for the explanation:

http://c-faq.com/stdio/getcharc.html

Upvotes: 4

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