fseek

I'm reading data from a file to memory that is opened with: FILE *f = fopen(path, "rb"); Before I start copying bytes from the file I seek to a start position using: /** * Goes to the given position of the given file. * * - Returns 0 on success * - Returns -1 on EOF * - Returns -2 if an error occured, see errno for error code * - Returns -3 if none of the above applies. This should never happen! */ static int8_t goto_pos(FILE *f, uint64_t pos) { int err = fseek(f, pos, SEEK_SET); if (err != 0) { if (feof(f) != 0) return -1; if (ferror(f) != 0) return -2; return -3; } return 0; } The problem is

What is the difference between ftello/fseeko and fgetpos/fsetpos? Both seem to be file pointer getting/setting functions that use opaque offset types to sometimes allow 64 bit offsets. Are they supported on different platforms or by different standards? Is one more flexible in the type of the offset it uses? And, by the way, I am aware of fgetpos/fsetpos and ftell/fseek , but this is not a duplicate. That question asks about ftell/fseek, and the answer is not applicable to ftello/fseeko. See Portable Positioning for detailed information on the difference. An excerpt: On some systems where text

http://www.cz88.net/ip/ http://www.ttlsa.com/php/php_cunzhen-ipdata/ #　　wget h http://6.scdx3.crsky.com/201307/qqwry0715.zip #　　unzip qqwry0715.zip #　　mv ip/qqwry.dat /data/site/test.ttlsa.com/qqwry.dat p class cls_ipAddress{ private $fp; private $firstip; private $lastip; private $totalip; public function __construct($filename="qqwry.dat"){ $this->fp=0; if(($this->fp=@fopen($filename,"rb"))!==false){ $this->firstip=$this->getlong(); $this->lastip=$this->getlong(); $this->totalip=($this->lastip-$this->firstip)/7; register_shutdown_function(array(&$this,"__destruct")); } } public function _

I've read posts that show how to use fseek and ftell to determine the size of a file. FILE *fp; long file_size; char *buffer; fp = fopen("foo.bin", "r"); if (NULL == fp) { /* Handle Error */ } if (fseek(fp, 0 , SEEK_END) != 0) { /* Handle Error */ } file_size = ftell(fp); buffer = (char*)malloc(file_size); if (NULL == buffer){ /* handle error */ } I was about to use this technique but then I ran into this link that describes a potential vulnerability. The link recommends using fstat instead. Can anyone comment on this? The link is one of the many nonsensical pieces of C coding advice from CERT

I have noticed two methods to return to the beginning of a file FILE *fp = fopen("test.bin", "r") fseek(fp, 0, SEEK_END); rewind(fp); and FILE *fp = fopen("test.bin", "r") fseek(fp, 0, SEEK_END); fseek(fp, 0, SEEK_SET); What would be difference if any between these methods? They are basically two different ways to accomplish the same thing: set the pointer to the beginning of the file. The only difference is that rewind also clears the error indicator. If given the choice, you should use fseek . This is because rewind doesn't return an integer indicating whether the operation has succeeded. If

I'm trying to append the contents of a file myfile.txt to the end of a second file myfile2.txt in c. I can copy the contents, but I can't find a way to append. Here's my code: FILE *pFile; FILE *pFile2; char buffer[256]; pFile=fopen("myfile.txt", "r"); pFile2=fopen("myfile2.txt", r+); if(pFile==NULL) { perror("Error opening file."); } else { while(!feof(pFile)) { if(fgets(buffer, 100, pFile) != NULL) { fseek(pFile2, -100, SEEK_END); fprintf(pFile2, buffer); } } fclose(pFile); fclose(pFile2); I don't think I'm using fseek correctly, but what I'm trying to do is call fseek to put the pointer at