sf_file(3) Library Functions Manual sf_file(3) NAME initfdpos, initFILEpos, adjfdpos, adjFILEpos -- file positions indicator handling SYNOPSIS #include <stdio.h> #include <strfunc.h> int initfdpos(const char *fname, int stream, const char *ext); int initFILEpos(const char *fname, FILE *stream, const char *ext); int adjfdpos(int stream, int posfd, int doSync); int adjFILEpos(FILE *stream, int posfd, int doSync); DESCRIPTION Those functions are used to maintain a file positions indicator between the program sessions. This is often needed when a process is being parsed a log file and tries to save current position within this log to start from this point later. int initfdpos(const char *fname, int stream, const char *ext) creates a po- sition indicator file "<fname>.<ext>", and returns its file descriptor. If the position file is already exists, then it advances stream's position ac- cording to the information derived from that file. initfdpos also checks the file size and inode changes in order to be robust in situations when file shrinked or replaced. int initFILEpos() is almost the same except that it takes a FILE * argument instead of plain file descriptor. Both functions returns position file descriptor, or -1 in case of failure. int adjfdpos(int stream, int posfd, int doSync) and adFILEdpos() writes the current position within the file referenced by stream into the posfd. If doSync is not zero, it also does fsync(2). Return values: 0 (Success) or -1 in case of any errors. EXAMPLE void main() { int posfd; FILE *logfile; char buf[1042]; logfile = fopen("file.log", "r"); if(!logfile) exit(EX_NOINPUT); while(fgets(buf, sizeof(buf), logfile)) { /* Do something ... */ adjFILEpos(logfile, posfd, 0); }; /* Force data to be flushed on disk. */ adjFILEpos(logfile, posfd, 1); fclose(logfile); close(posfd); }; SEE ALSO strfunc(3). AUTHORS Lev Walkin <vlm@lionet.info> FreeBSD ports 15.quarterly December 4, 2000 sf_file(3)
NAME | SYNOPSIS | DESCRIPTION | EXAMPLE | SEE ALSO | AUTHORS
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