unable to reset and move the pointer

[karthigeyantp]

hi,

i have a problem in resetting and unable to move the pointer in the text file using seekg()function in c++. what to do ??

[gpraghuram]

R u checking what the seekg is returning and whether the file is having that much bytes in it...


raghu

[karthigeyantp]

R u checking what the seekg is returning and whether the file is having that much bytes in it...


raghu

when i reset it to starting point by
file.seekg(0,io s::beg);
after this through file.tellg() it shows this number 4294967295
so it has not resetted, i don't know what to do. my max file size is 65751180.

[gpraghuram]

when i reset it to starting point by
file.seekg(0,io s::beg);
after this through file.tellg() it shows this number 4294967295
so it has not resetted, i don't know what to do. my max file size is 65751180.

Usually it dosent behave that way.
I tried a small piece of code and it printed the value properly.
Can you post the piece of code on how u are doing the seek and tell?


Raghu

[karthigeyantp]

my loc value= 6575910

file.clear();
file.seekg(0,io s::beg);
locat=distance. tellg();
cout<<"locat= "<<locat<<" \n";
file.seekg(loc) ;
loc1=fil.tellg( );
cout<<"after move"<<loc1;

after resetting to staring point the tellg() is showing -1. After moveing to some position i.e loc=6575910. but after this the tellg() is showing 42949672951.

[TamusJRoyce]

Please tell us the compiler & version you are trying to use. I've had this problem on MinGW gcc 3.4 (from dev-cpp). The MinGW from Codeblocks solved this for me, but I dunno if it would be a compiler problem for you or not...

[gpraghuram]

my loc value= 6575910

file.clear();
file.seekg(0,io s::beg);
locat=distance. tellg();
cout<<"locat= "<<locat<<" \n";
file.seekg(loc) ;
loc1=fil.tellg( );
cout<<"after move"<<loc1;

after resetting to staring point the tellg() is showing -1. After moveing to some position i.e loc=6575910. but after this the tellg() is showing 42949672951.

Why r u calling the clear() function as it is only for resetting the error state flags.
Can you try this fater commenting the clear function call.

Raghu

[karthigeyantp]

Why r u calling the clear() function as it is only for resetting the error state flags.
Can you try this fater commenting the clear function call.

Raghu

i tried without using the clear() fun.. also, but same result is comeing . i don,t know what to do.

[Banfa]

4294967295 = 0xFFFFFFFF or -1 in 32 bits. The tell failed in all circumstances. This suggests that the seek failed (that is the most likely cause of the tell failing).

You need to work out why your seek failed. Since you are trying to seek to the start of the file which should work for pretty much any file it must be something else.

Have you verified that the file is actually open?
Have you stepped through the code using a debugger?

[karthigeyantp]

Please tell us the compiler & version you are trying to use. I've had this problem on MinGW gcc 3.4 (from dev-cpp). The MinGW from Codeblocks solved this for me, but I dunno if it would be a compiler problem for you or not...

i am using gcc( 3.4.2) compiler in linux

[gpraghuram]

As suggested by Banfa its better you debug the code and find the issue.
As told by me i tried a small piece of code and it worked.

Raghu

[karthigeyantp]

R u checking what the seekg is returning and whether the file is having that much bytes in it...


raghu

i am new to linux may i know how to debug the c++ code

[gpraghuram]

i am new to linux may i know how to debug the c++ code

You have to use gdb to debug the code.
gdb <exename>
Better read the help of gdb before starting to work with gdb.


Raghuram