CODEWITHSUNDEEP
clinuxfilesystem-callserrno
Jah
Jah

Reputation: 1039

lseek EOVERFLOW error handling

I've noticed that when I try to seek more bytes than off_t can represent I get an EOVERFLOW error. How can I seek more than the bigger number in off_t?

Upvotes: 1

Views: 1363

Answers (2)

Jim Balter
Jim Balter

Reputation: 16406

See http://www.kernel.org/doc/man-pages/online/pages/man3/lseek64.3.html

Upvotes: 0

Ignacio Vazquez-Abrams
Ignacio Vazquez-Abrams

Reputation: 798566

Enable large file support.

In a nutshell for using LFS you can choose either of the following:

  • Compile your programs with "gcc -D_FILE_OFFSET_BITS=64". This forces all file access calls to use the 64 bit variants. Several types change also, e.g. off_t becomes off64_t. It's therefore important to always use the correct types and to not use e.g. int instead of off_t. For portability with other platforms you should use getconf LFS_CFLAGS which will return -D_FILE_OFFSET_BITS=64 on Linux platforms but might return something else on e.g. Solaris. For linking, you should use the link flags that are reported via getconf LFS_LDFLAGS. On Linux systems, you do not need special link flags.
  • Define _LARGEFILE_SOURCE and _LARGEFILE64_SOURCE. With these defines you can use the LFS functions like open64 directly.
  • Use the O_LARGEFILE flag with open to operate on large files.

Upvotes: 6

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