pread(2) System Calls Manual pread(2) pread, pwrite - (libc -lc) #include ssize_t pread(size_t count; int fd, void buf[count], size_t count, off_t offset); ssize_t pwrite(size_t count; int fd, const void buf[count], size_t count, off_t offset); glibc ( feature_test_macros(7)): pread() pwrite(): _XOPEN_SOURCE >= 500 || /* glibc 2.12: */ _POSIX_C_SOURCE >= 200809L pread() count fd offset ( ) buf. . pwrite() count buf fd offset. . fd . pread() ( ) pwrite() . ( read(2) write(2)). -1 errno . pread() errno read(2) lseek(2). pwrite() errno write(2) lseek(2). POSIX.1-2024. POSIX.1-2001. Linux 2.1.60 i386 Linux 2.1.69. C ( lseek(2) ) glibc 2.1. C Linux Linux 2.6: pread() pread64() pwrite() pwrite64(). . pread() pwrite() glibc . 32 syscall(2). pread() pwrite() . / . POSIX O_APPEND pwrite() . Linux O_APPEND pwrite() offset. lseek(2) read(2) readv(2) write(2) 3 . . : . 6.18 8 2026 pread(2)