fseeko(3) Library Functions Manual fseeko(3) fseeko, ftello - (libc -lc) #include int fseeko(FILE *stream, off_t offset, int whence); off_t ftello(FILE *stream); glibc ( feature_test_macros(7)): fseeko() ftello(): _FILE_OFFSET_BITS == 64 || _POSIX_C_SOURCE >= 200112L fseeko() ftello() fseek(3) ftell(3) ( fseek(3)) offset fseeko() ftello() off_t long. off_t long 32- _FILE_OFFSET_BITS 64 ( ) off_t 64-. fseeko() 0 ftello() . -1 errno . fseek(3). attributes(7). +------------+------------------------------------+--------------------+ || | | +------------+------------------------------------+--------------------+ |fseeko() | | MT-Safe | |ftello() | | | +------------+------------------------------------+--------------------+ POSIX.1-2008. glibc 2.1. POSIX.1-2001, SUSv2. _LARGEFILE_SOURCE. fseek(3) 3 . . : . 6.18 8 2026 fseeko(3)