Value (computer science)
In C: L-value and r-value
Some languages use the idea of l-value and r-value. L-values are values that have addresses, meaning they are variables or dereferenced references to a certain place. R-value is either l-value or non-l-value — a term only used to distinguish from l-value. In C, the term l-value originally meant something that could be assigned (coming from left-value, indicating it was on the left side of the = operator), but since 'const' was added to the language, this now is termed a 'modifiable l-value'.
An l-value is an expression that designates (refers to) an object. A non-modifiable l-value is addressable, but not assignable. A modifiable l-value allows the designated object to be changed as well as examined. An r-value is any expression that is not an l-value, it refers to a data value that is stored at some address in memory.
2006-09-29
2006-09-28
NTFS sucks!
In cygwin with NTFS of WindowsXP sp2 environment, I''d input:
mv uClinux-dist /usr/local/src
take me about 30minutes, it's really sucks!!
In Linux box, the inode will help it shorter. But why? Let me study in the Ch.11 FileSystem.
mv uClinux-dist /usr/local/src
take me about 30minutes, it's really sucks!!
In Linux box, the inode will help it shorter. But why? Let me study in the Ch.11 FileSystem.
patch -p0
-pnum or --strip=num
Strip the smallest prefix containing num leading slashes from each file name found in the patch file. A sequence of one or more adjacent slashes is counted as a single slash. This controls how file names found in the patch file are treated, in case you keep your files in a different directory than the person who sent out the patch. For example, supposing the file name in the patch file was
/u/howard/src/blurfl/blurfl.c
setting -p0 gives the entire file name unmodified, -p1 gives
u/howard/src/blurfl/blurfl.c
without the leading slash, -p4 gives
blurfl/blurfl.c
and not specifying -p at all just gives you blurfl.c. Whatever you end up with is looked for either in the current directory, or the directory specified by the -d option.
Strip the smallest prefix containing num leading slashes from each file name found in the patch file. A sequence of one or more adjacent slashes is counted as a single slash. This controls how file names found in the patch file are treated, in case you keep your files in a different directory than the person who sent out the patch. For example, supposing the file name in the patch file was
/u/howard/src/blurfl/blurfl.c
setting -p0 gives the entire file name unmodified, -p1 gives
u/howard/src/blurfl/blurfl.c
without the leading slash, -p4 gives
blurfl/blurfl.c
and not specifying -p at all just gives you blurfl.c. Whatever you end up with is looked for either in the current directory, or the directory specified by the -d option.
2006-09-14
Google Reader -> Bloglines
Ya, I did it in today, 'cuz the AJAX operation is such slowly in Opera 9.00, and some error often occured in operation. So that, I exported all of feed to bloglines.
My buddy, Howl suggests me some useful RSS reader, I've never tried it yet, 'cuz now I prefer the on-line service (a.k.a API application). Maybe next time, I'll try these good tool. :-)
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