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Open large files on 32-bit OS and ANSI C

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Karel:
Using ANSI C, is there already a way to read/write large files (> 2.1 4.2GB) on a 32-bit OS?

ledtester:
It will depend on the OS.

For Linux/Unix I found this:

Portable support for large files
https://stackoverflow.com/a/30867832

which points to calls such as fseeko(), ftello(), fseeko64(), ftello64() and lseek64().

For WinXP SP2 you have the Set/GetFilePointerEx() pair of calls.

Karel:

--- Quote from: ledtester on August 27, 2023, 01:45:40 pm ---It will depend on the OS.

For Linux/Unix I found this:

Portable support for large files
https://stackoverflow.com/a/30867832

which points to calls such as fseeko(), ftello(), fseeko64(), ftello64() and lseek64().

For WinXP SP2 you have the Set/GetFilePointerEx() pair of calls.

--- End quote ---

It's not  ANSI C

ejeffrey:
Yes.  You can fopen() a file of any size and read it continuously until EOF.

What you can't do is fseek() in a single step. Although technically you can call fseek(fh, LONG_MAX, SEEK_CUR) in a loop to advance to an arbitrary position.

Karel:

--- Quote from: ejeffrey on August 27, 2023, 03:13:37 pm ---Yes.  You can fopen() a file of any size and read it continuously until EOF.

What you can't do is fseek() in a single step. Although technically you can call fseek(fh, LONG_MAX, SEEK_CUR) in a loop to advance to an arbitrary position.

--- End quote ---

Interesting. But the limitation of fseek(0 and ftell() seems cumbersome.

It's weird that ANSI C has never been updated with 64-bit variants (that work on 32-bit hosts).

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