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How to concatenate twice with the C preprocessor and expand a macro as in “arg ## _ ## MACRO”?
...ard C Preprocessor
$ cat xx.c
#define VARIABLE 3
#define PASTER(x,y) x ## _ ## y
#define EVALUATOR(x,y) PASTER(x,y)
#define NAME(fun) EVALUATOR(fun, VARIABLE)
extern void NAME(mine)(char *x);
$ gcc -E xx.c
# 1 "xx.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "xx.c"
extern void mi...
How do I use prepared statements in SQlite in Android?
... Below are some examples:
Create a table
String sql = "CREATE TABLE table_name (column_1 INTEGER PRIMARY KEY, column_2 TEXT)";
SQLiteStatement stmt = db.compileStatement(sql);
stmt.execute();
The execute() method does not return a value so it is appropriate to use with CREATE and DROP but not in...
What is the combinatory logic equivalent of intuitionistic type theory?
... bracket abstraction.
tm :: Tm a -> Unty a
tm (Var a) = V a
tm (Lam _ b) = bra (tm b)
tm (f :$ a) = tm f :. tm a
tm (Pi a b) = C P :. tm a :. tm b
tm Set = C U
bra :: Unty (Su a) -> Unty a -- binds a variable, building a function
bra (V Ze) = C S :. C K :. C...
Practical usage of setjmp and longjmp in C
...y to verify that).
#include <stdio.h>
#include <setjmp.h>
jmp_buf bufferA, bufferB;
void routineB(); // forward declaration
void routineA()
{
int r ;
printf("(A1)\n");
r = setjmp(bufferA);
if (r == 0) routineB();
printf("(A2) r=%d\n",r);
r = setjmp(buffer...
Convert an image (selected by path) to base64 string
...e to retrieve the base64 string
public static string ImageToBase64(string _imagePath)
{
string _base64String = null;
using (System.Drawing.Image _image = System.Drawing.Image.FromFile(_imagePath))
{
using (MemoryStream _mStream = new MemoryStream())
...
Objective-C : BOOL vs bool
...
From the definition in objc.h:
#if (TARGET_OS_IPHONE && __LP64__) || TARGET_OS_WATCH
typedef bool BOOL;
#else
typedef signed char BOOL;
// BOOL is explicitly signed so @encode(BOOL) == "c" rather than "C"
// even if -funsigned-char is used.
#endif
#defin...
Alternatives to gprof [closed]
... in this way:
g++ -m64 -fno-omit-frame-pointer -g main.cpp -L. -ltcmalloc_minimal -o my_test
I use libmalloc_minimial.so since it is compiled with -fno-omit-frame-pointer while libc malloc seems to be compiled without this option.
Then I run my test program
./my_test 100000000
Then I record ...
Why does “_” (underscore) match “-” (hyphen)?
...
Because the underscore _ is a wildcard like the percent %, except that it only looks for one character.
SQL pattern matching enables you to use "_" to match any single character and "%" to match an arbitrary number of characters (including zero...
while (1) vs. while(True) — Why is there a difference (in python 2 bytecode)?
...oes.
Here's 2.7:
>>> dis.dis('True == 1')
1 0 LOAD_GLOBAL 0 (True)
3 LOAD_CONST 1 (1)
6 COMPARE_OP 2 (==)
9 RETURN_VALUE
>>> dis.dis('True == 1')
1 0 LOAD_GLOBAL ...
Speed comparison with Project Euler: C vs Python vs Erlang vs Haskell
...
Using GHC 7.0.3, gcc 4.4.6, Linux 2.6.29 on an x86_64 Core2 Duo (2.5GHz) machine, compiling using ghc -O2 -fllvm -fforce-recomp for Haskell and gcc -O3 -lm for C.
Your C routine runs in 8.4 seconds (faster than your run probably because of -O3)
The Haskell solution runs in...