The code currently does this and the fgetpos does handle files larger than 4GB but the seek returns an error, so any idea how to seek to the end of a file >4GB? fpos_t currentpos; sok=fseek(fp,0,SEEK_END); assert(sok==0,"Seek error!"); fgetpos(fp,¤tpos); m_filesize=currentpos; ...
I have a situation in a code where there is a huge function that parses records line-by-line, validates and writes to another file. In case there are errors in the file, it calls another function that rejects the record and writes the reject reason. Due to a memory leak in the program, it crashes with SIGSEGV. One solution to kind of ...
Is using fseek to backtrack character fscanf operations reliable? Like for example if I have just fscanf-ed 10 characters but I would like to backtrack the 10 chars can I just fseek(infile, -10, SEEK_CUR) ? For most situations it works but I seem to have problems with the character ^M. Apparently fseek registers it as a char but fscan...
Hi, What I need is an equivalent for PHP's fseek() function. The function works on files, but I have a variable that contains binary data and I want to work on it. I know I could use substr(), but that would be lame - it's used for strings, not for binary data. Also, creating a file and then using fseek() is not what I am looking for ei...
As I loop through lines in file A, I am parsing the line and putting each string (char*) into a char**. At the end of a line, I then run a procedure that consists of opening file B, using fgets, fseek and fgetc to grab characters from that file. I then close file B. I repeat reopening and reclosing file B for each line. What I would ...
My previous Question is about raw data reading and writing, but a new problem arised, it seems there is no ending.... The question is: the parameters of the functions like lseek() or fseek() are all 4 bytes. If i want to move a span over 4G, that is imposible. I know in Win32, there is a function SetPointer(...,Hign, Low,....), this po...
Q: I'm trying to update a file in place, by using fopen mode "r+", reading a certain string, and writing back a modified string, but it's not working. A: Be sure to call fseek before you write, both to seek back to the beginning of the string you're trying to overwrite, and because an fseek or ff...
I have a file. I read the size of file. Then I loop reading two bytes at a time until I get to the end of the file. After every read operation I increment the current position by 2, however the position does not get incremented after I get to half the size of the file, the fread operation will read 0 bytes. the program reads the file si...
Hi there, we have a C++ class which basically reads and writes vectors from a binary file. An exemplary read function that loads a single vector into memory looks like this: int load (const __int64 index, T* values) const { int re = _fseeki64(_file, index * _vectorSize + _offsetData, SEEK_SET); assert(re == 0); size_t read = frea...
I'm trying to read the last 50 characters in a file by doing this: FILE* fptIn; char sLine[51]; if ((fptIn = fopen("input.txt", "rb")) == NULL) { printf("Coudln't access input.txt.\n"); exit(0); } if (fseek(fptIn, 50, SEEK_END) != 0) { perror("Failed"); fclose(fptIn); exit(0); } fgets(sLine, 50, fptIn); printf("%s", ...
This is not a pure programming question, however it impacts the performance of programs using fseek(), hence it is important to know how it works. A little disclaimer so that it doesn't get closed. I am wondering how efficient it is to insert data in the middle of the file. Supposing I have a file with 1MB data and then I insert somethi...
Can you set any index of array as starting index i.e where to read from file? I was afraid if the buffer might get corrupted in the process. #include <stdio.h> int main() { FILE *f = fopen("C:\\dummy.txt", "rt"); char lines[30]; //large enough array depending on file size fpos_t index = 0; while(fgets(&lines[index], ...
How do I read a file backwards line by line using fseek? code can be helpful. must be cross platform and pure php. many thanks in advance regards Jera ...
how do I do this. the file can get very big, so good performance is necessary code is helpful. this is what i have so far function prepend($string, $filename) { $context = stream_context_create (); $fp = fopen($filename,'r',1,$context); $tmpname = md5($string); file_put_contents($tmpname,$string); file_put_co...
I require to add a string before 45byte in an existing file. I tried using fseek as bellow. int main() { FILE *fp; char str[] = "test"; fp = fopen(FILEPATH,"a"); fseek(fp,-45, SEEK_END); fprintf(fp,"%s",str); fclose(fp); return(0); } I expected that this code will add "test" in before 45 char from EOF...
I have a process master that spawns N child processes that communicate with the parent through unnamed pipes. I must be able to: make the father open the file and then send, to each child, a struct telling that it has to read from min to max line; this is going to happen at the same time, so I don't know: 1st how to divide total_lines ...
I am trying to find how to store and process (search, add, remove) an array of linked lists on disk. For example in memory, it would like struct list { int a; struct list *next; }LIST LIST *array[ARRAY_SIZE] int main{ ... LIST *foo = array[pointer]; /* Search */ while(foo!=NULL){ ... foo=foo->next } } I believe that by ...
I have a binary file in CSV format that contains multiple records. Each record is entered in as user_name, last_name, first_name, num_wins, num_losses, num_ties. I am creating a method to update a certain players record of wins,losses and ties. The user inputs the username to change followed by the changes to the wins, losses and ties. ...