lseek - glibc

Split from the chapter glibc: stdio and Formatted I/O into the per-function layout; see the method page and the glibc ledger for coverage status.

Signature – off_t lseek(int fd, off_t offset, int whence);

Libc side – returns the resulting offset or (off_t)-1+errno (ESPIPE on pipes). SEEK_SET/SEEK_CUR/SEEK_END are shared with fseek. lseek(fd, 0, SEEK_CUR) is the idiom for reading the position (manual, File Position Primitive). lseek64 (LFS) exists for 32-bit hosts; with _FILE_OFFSET_BITS == 64 lseek maps to it. The descriptor-side model (shared OFD offsets, ESPIPE, sparse-file SEEK_HOLE/SEEK_DATA GNU extensions) is the lseek entry of Descriptors and File I/O.