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 ... |
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, ... |
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 ... |
I'm testing this code, but doesn't work, it always says that an error occurred :S
int main(int argc, char **argv) {
FILE *file_pointer;
file_pointer = fopen("text.txt","r");
...
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What's the difference between fgetpos/fsetpos and ftell/fseek?
What are fgetpos and fsetpos good for?
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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 ... |
can you help me figure out what's the problem in my code.. i wanted to edit a specific line.... thnx
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main (){
char arr[50];
char ...
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I'm trying to write a FUSE filesystem that presents streamable music as mp3 files. I don't want to start to stream the audio when just the ID3v1.1 tag is read, so ... |
Is there an equivalent of fseek for fd? I've been using int fds for a very long time, and want to use fseek... but I know there is no seek function.
Thanks ... |
I will appreciate your advice on the following. I'am developing a video converter which based on FFmpeg's libavformat, and I need to implement an accurate seeking API. First of all, I ... |
Basically I want to write data to a file at a particular position and don't want to load data in to the memory for sorting it. For example if I have ... |
I have opened a file using a and r+ but when I use fseek and ftell the file pointer is always 0.
My file looks like this:
1 -3 ...
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I'm trying to solve a K&R exercise(7.7).It asks writing a program which takes filenames as arguments and searches them for a particular pattern.For the pattern matching I use the sliding window ... |
Im reading a specified chunk of a file with fseek and fread functions and then writing it to another file. For some reason in the destination file I get about 20 ... |
Is a memory page loaded to main memory for each fread/fseek on a file?
I am trying to implement a byte wise hashing along with BTREE in between , (i.e) If the ... |
I am writing an audio file to an SD/MMC storage card in real time, in WAVE format, working on an ARM board. Said card is (and must remain) in ... |
P: n/a thomas.mertes@gmx.at Hello Recently I discovered some problem. I have some C code which determines how many bytes are available in a file. Later I use this information to malloc a buffer of the correct size before I read the bytes. Determining the number of bytes available in a file is done in 5 steps: 1. Use tell(aFile) to get ... |
in parallel programing a processor executes a part of the job, but in multi-thread programming whole job is done by one processor. This statement is absolutely false. A parallel program is a program where sections are run in parallel in real time. This requires multiple processors. Each processor runs a section. Each section is called a thread. A multi-threaded program is ... |
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From position 1 in the file (the SECOND byte), add the value in column-3. Now the question is: Does your column-3 contain the NUMBER of columns or the number of bytes in the number of columns? fseek ASSUMES the second argument is the OFFSET from the third argument. thanks a lot much for clearing my doubt. but the question you ve ... |
ericunfuk I have posted a few other posts before this one today, I still can't solve my problem, I think I need to elaborate my problem now. I'm trying to send a file using UDP, below is a segment of my sender app, the sender and the receiver are both on the same machine and I have an Internet emulation gateway ... |
#include #include #include #include typedef struct { int integer; char string[12]; } RECORD; #define NRECORDS (50) int main () { RECORD record; int i; FILE *fp; fp = fopen("records.dat", "w+"); for (i=0; i |
23. fseek problem cboard.cprogramming.com#include #include int main(int argc, char **argv) { FILE *file_handle; long int file_length; file_handle = fopen("file.bin","rb"); if(fseek(file_handle, 0, SEEK_END)) { puts("Error while seeking to end of file"); return 1; } file_length = ftell(file_handle); if (file_length < 0) { puts("Error while reading file position"); return 2; } printf("File length: %d bytes\n", file_length); fclose(file_handle); getch(); return(0); } |
Code: The fseek value: -6. Token to be processed: 1123.123TESTa. Next Token: TESTa The fseek value: -6. Token to be processed: 2123.123TESTb. Next Token: 3TESTb -Next_Line- The fseek value: -6. Token to be processed: 3123.123TESTc. Next Token: TESTc The fseek value: -6. Token to be processed: 4123.123TESTd. Next Token: 3TESTd -Next_Line- The fseek value: -6. Token to be processed: 5123.123TESTe. Next ... |
Having some troubles. The idea is that if the file size is greater than 100 bytes, then the file is sought to the 100th to last byte. Then the file is printed to the screen. I'm getting a segfault at the fseek for >100 files, and a segfault at the getc. GDB isn't really helping explain why (for my knowledge base). ... |
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27. fseek explain cboard.cprogramming.comOriginally Posted by man fseek FSEEK(3) Linux Programmer's Manual FSEEK(3) NAME fgetpos, fseek, fsetpos, ftell, rewind - reposition a stream SYNOPSIS #include int fseek(FILE *stream, long offset, int whence); long ftell(FILE *stream); void rewind(FILE *stream); int fgetpos(FILE *stream, fpos_t *pos); int fsetpos(FILE *stream, fpos_t *pos); DESCRIPTION The fseek() function sets the file position indicator for the stream pointed to by ... |
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Hi all, I have a file consisting of a huge array of floats written in binary mode (fwrite). Its actually a contiguous 2D array. I need to access various parts of the array and for this I use fseek to jump a different point and the fread to read in the data. I noticed that some of my output coming out ... |
Vanity of vanities, saith the Preacher, vanity of vanities; all is vanity. What profit hath a man of all his labour which he taketh under the sun? All the rivers run into the sea; yet the sea is not full; unto the place from whence the rivers come, thither they return again. For in much wisdom is much grief: and he ... |
[code] #include #include #include #include Ok.. so that is just a fixed up version of your code as-is. There are some issues with it that are important to realize. You are not keeping track of wrong answers at all. You should probably just exit the program if you cannot open the question file. And you never did ... |
t Open in text (translated) mode. In this mode, CTRL+Z is interpreted as an end-of-file character on input. In files opened for reading/writing with "a+", fopen checks for a CTRL+Z at the end of the file and removes it, if possible. This is done because using fseek and ftell to move within a file that ends with a CTRL+Z, may cause ... |
I'm utterly surprised that IT "WORKS" at all. By all means, this code should crash. The variable string is a pointer to char that hasn't been given a value, so when you do scanf() you are reading into a undefined memory location - you are just "lucky" enough that it doesn't crash immediately [actualy, if I make a mistake where I ... |
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I am writing a program that saves all of its input to a binary file. I have three entries: your code(1-5), date, and sale amount. I have the program storing everything in the file, but I need to access information by the code that it was entered under. The first function retrieves the corresponding name for the code entered and them ... |
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define EMAILADDRLEN 90 // this is set above in the program int e_loc = 98; // this is set above in the program if ( (out = fopen("gorseve_10774.csv","w")) != NULL ) { while ( (returnCode = fgets(lineOfText, LINESIZE, in )) != NULL) { e_loc = parseGorseveRecord(lineOfText); printf("location found %d\n", e_loc); if ( (ret = fseek(out, e_loc, SEEK_CUR)) == 0 ) { ... |
38. Reg. fseek cboard.cprogramming.comIf the size of the records is not known in advance, the only way to do it is by starting at the beginning and reading one line at a time until you reach the line you're interested in. If you use newline termination on each record and your records are text, not binary, fgets() should work nicely for this. If this ... |
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hi there: just a quick question. i have been working on this code which reads a file that contains information about each frame for animation (blm files). my code is controled my a GUI(slider) and then uses fseek() to locate the frame to be read. a bit like a scraching. my questions is that, does fseek() eats a lot of cpu ... |
You don't "read in a character where the cursor is". You simply read a character. The cursor position has nothing to do with reading a character. It is an output item. If you want to "read the character that's currently under the cursor", then you'll need to keep track of the screen's contents in a buffer some place, and seek around ... |
Hello, I'm having problems learning about rand access files... Most of my code works, all until you get to the fseek. The output is all garbaled, I'm not sure why. I'll post the entire code, so that if it's something other than the fseek that is affecting it, you could point that out... Thanks Code: #include #include #include ... |
43. fseek cboard.cprogramming.com |
Hello Everyone, I am writing a program that does a whois and nslookup on domains listed in a text file. I am having a problem with popen and fseek. Here is the code: Code: #include #include int main() { FILE *fptr1, *fptr2, *domreadout, *nsreadout; char filename1[] = "virt.txt"; char filename2[] = "output.txt"; char buff[BUFSIZ]; char whoiscommand[150]; char nscommand[150]; char ... |
45. fseek ??? cboard.cprogramming.com |
I am trying to use fseek to overwrite data in a file , the code works but its printing the new information to be written at the end of the line in which the data is found. Code: void updaterecord(void) { system("color 2"); struct custinfo info; FILE *customer1; customer1=fopen("customer1.txt","r"); if (customer1==NULL) printf("\n\n\t\t\t FILE WAS NOT FOUND "); else { char choice4; ... |
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#include char initXMLDoc(int systemNumber, char *fileName); int main() { FILE *fp; printf("\nInit XML doc"); initXMLDoc(1234, "files/test.xml"); if((fp = fopen("files/test.xml", "a+b"))==NULL){ printf("\nFailed to open file"); return -1; } fseek(fp, 9, SEEK_END); fwrite("HELLO", 1, 12,fp); fclose(fp); return (0); } char initXMLDoc(int systemNumber, char *fileName){ FILE *fp; if((fp=fopen(fileName, "w"))==NULL){ printf("Failed to create initial XML document"); return 0; } // write encoding msg //fprintf(fp, ... |
49. fseek() forums.devshed.com |
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x=0; fseek(fp2, sizeof(rec)*index[x].pos, SEEK_SET); fread(&rec, sizeof(rec), 1, fp2); printf("%i ", rec.id); printf("%s ", rec.subject); printf("%i ", rec.year); printf("%i ", rec.month); printf("%i ", rec.day); printf("%s ", rec.state); printf("%s ", rec.county); printf("%f ", rec.length); printf("%s ", rec.code); while(!feof(fp2)) { x++; fseek(fp2, sizeof(rec)*index[x].pos, SEEK_SET); fread(&rec, sizeof(rec), 1, fp2); printf("%i ", rec.id); printf("%s ", rec.subject); printf("%i ", rec.year); printf("%i ", rec.month); printf("%i ", rec.day); printf("%s ... |
>> Why are you using low-level file i/o?? Just use FILE* and all will be ok. The only reason to use open() is when the compiler for the target operating system doesn't have FILE* and associated functions. I inherited a lot of code from the last guy and need to change it. He used file descriptors, so I'm stuck with them ... |
53. fseek() daniweb.comvoid updaterecord(void) { system("color 2"); struct custinfo info; FILE *customer1; customer1=fopen("customer1.txt","r"); if (customer1==NULL) printf("\n\n\t\t\t FILE WAS NOT FOUND "); else { char choice4; char Target[50]; int Found=0; if((customer1=fopen("customer1.txt","r"))==NULL) printf("THE FILE IS EMPTY"); else { printf("\n\n\t\t ENTER ID NUM:"); scanf("%s",&Target); while(!feof(customer1)&& Found==0) { fscanf(customer1,"%s %s %s %s %s %s %s %s",info.regis,info.Name,info.address,info.number,info.dob,info.treatment,info.allergies,info.app); if(strcmp(Target,info.regis)==0) Found=1; } if(Found) { printf("\n\t\t REGISTRATION:%s\n",info.regis); printf("\n\t\t NAME:%s\n",info.Name); printf("\n\t\t ADDRESS:%s\n",info.address); ... |
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#include #include int main(void){ FILE * input; char * nlptr; long position; long count; char ch; int name[81]; fprintf(stdout, "please enter a text file\n"); fgets(name, 81, stdin); nlptr = strchr(name, '\n'); if(nlptr) *nlptr ='\0'; input = fopen(name, "r"); printf("enter a file position\n"); fscanf(stdin, "%d", &position); while(getchar() != '\n') continue; for(count = position; getc(input) != '\n'; count++){ fseek(input, count, SEEK_SET); ... |
I'm relatively new to fseek, so I really don't know if I'm using this call right. I want to move a file in chunks of 256 bytes at a time, but for some reason, I either get only 256 bytes to the file I'm writing to or an appending of all files into one. What am I doing wrong?FILE ... |