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Platform independent size_t Format specifiers in c?
...
Yes: use the z length modifier:
size_t size = sizeof(char);
printf("the size is %zu\n", size); // decimal size_t ("u" for unsigned)
printf("the size is %zx\n", size); // hex size_t
The other length modifiers that are available are hh (for char), h (for short), l (for long),...
What is the purpose of std::make_pair vs the constructor of std::pair?
...two = make_pair (10.5,'A'); // ok: implicit conversion from pair<double,char>
Aside from the implicit conversion bonus of it, if you didn't use make_pair you'd have to do
one = pair<int,int>(10,20)
every time you assigned to one, which would be annoying over time...
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Reading large text files with streams in C#
...to memory, loads faster as it doesn't make a new string every time you add chars)
– Joshua G
Jan 20 '16 at 15:01
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Replacing a 32-bit loop counter with 64-bit introduces crazy performance deviations with _mm_popcnt_
...;
#include <chrono>
#include <x86intrin.h>
int main(int argc, char* argv[]) {
using namespace std;
uint64_t size=1<<20;
uint64_t* buffer = new uint64_t[size/8];
char* charbuffer=reinterpret_cast<char*>(buffer);
for (unsigned i=0;i<size;++i) charbuffer[i]=...
Why is it impossible to build a compiler that can determine if a C++ function will change the value
... /* modify variable */
variable = 1;
}
}
int main(int argc, char **argv) {
if (modifies_variable(f, variable)) {
printf("Modifies variable\n");
} else {
printf("Does not modify variable\n");
}
return 0;
}
...
Elegant Python function to convert CamelCase to snake_case?
...etHTTPResponseCode').lower()
'get_httpresponse_code'
To ignore the first character simply add look behind (?!^)
>>> re.sub('(?!^)([A-Z]+)', r'_\1','CamelCase').lower()
'camel_case'
>>> re.sub('(?!^)([A-Z]+)', r'_\1','CamelCamelCase').lower()
'camel_camel_case'
>>> re.su...
What is a bus error?
...*/
int main() {
int fd;
int *map;
int size = sizeof(int);
char *name = "/a";
shm_unlink(name);
fd = shm_open(name, O_RDWR | O_CREAT, (mode_t)0600);
/* THIS is the cause of the problem. */
/*ftruncate(fd, size);*/
map = mmap(NULL, size, PROT_READ | PROT_WRITE, MA...
What is the maximum number of characters that nvarchar(MAX) will hold?
I'm new to the concept nvarchar(MAX) . How many characters will it hold?
3 Answers
3
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How can I negate the return-value of a process?
...#include <sys/wait.h>
#include "stderr.h"
#ifndef lint
static const char sccs[] = "@(#)$Id: not.c,v 4.2 2005/06/22 19:44:07 jleffler Exp $";
#endif
int main(int argc, char **argv)
{
int pid;
int corpse;
int status;
err_setarg0(argv[0]);
...
When should you not use virtual destructors?
...ays that if you were to copy from an object with POD type into an array of chars (or unsigned chars) and back again, then the result will be the same as the original object.]
Modern C++
In recent versions of C++, the concept of POD was split between the class layout and its construction, copying a...