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how to insert and delete characters in the middle of file
Post 56672 by mbb on Thursday 7th of October 2004 01:10:30 PM
10-07-2004
Quote:
Originally posted by Driver
> If you have the memory, you might want to read the whole file into memory, manipulate it there and then dump the results back to disk.
Well, if one really wants to modify it in memory, one could also mmap() the file. Using MAP_SHARED you won't need any memory to back the file, as it is already done by the disk. memmove() to move data to make room/overwrite areas of the file and ftruncate() to grow/shrink the file. But I do not recommend this because it likely does not buy anything and may well be slower, requires more effort and decreases the degree of portability.
> If you have the memory, you might want to read the whole file into memory, manipulate it there and then dump the results back to disk.
Well, if one really wants to modify it in memory, one could also mmap() the file. Using MAP_SHARED you won't need any memory to back the file, as it is already done by the disk. memmove() to move data to make room/overwrite areas of the file and ftruncate() to grow/shrink the file. But I do not recommend this because it likely does not buy anything and may well be slower, requires more effort and decreases the degree of portability.
My point to the OP was quite simple and old fashioned: memory is faster than disk!
( I hope that is still true these days
)Peace
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LEARN ABOUT SUNOS
has_ic
has_ic(3XCURSES) X/Open Curses Library Functions has_ic(3XCURSES) NAME
has_ic, has_il - determine insert/delete character/line capability SYNOPSIS
cc [ flag... ] file... -I /usr/xpg4/include -L /usr/xpg4/lib -R /usr/xpg4/lib -lcurses [ library... ] c89 [ flag... ] file... -lcurses [ library... ] #include <curses.h> bool has_ic(void); bool has_il(void); DESCRIPTION
The has_ic() function determines whether or not the terminal has insert/delete character capability. The has_il() function determines whether or not the terminal has insert/delete line capability. RETURN VALUES
The has_ic() function returns TRUE if the terminal has insert/delete character capability and FALSE otherwise. The has_il() function returns TRUE if the terminal has insert/delete line capability and FALSE otherwise. ERRORS
None. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Unsafe | +-----------------------------+-----------------------------+ SEE ALSO
libcurses(3XCURSES), attributes(5), standards(5) SunOS 5.10 5 Jun 2002 has_ic(3XCURSES)