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#define macro for debug printing in C?
...
#include <stdarg.h>
#include <stdio.h>
void dbg_printf(const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
vfprintf(stderr, fmt, args);
va_end(args);
}
You can also use this technique in C99, of course, but the __VA_ARGS__ technique is neater because it uses re...
What is the difference between printf() and puts() in C?
...e (except for the added newline) if the string doesn't contain any control characters (%) but if you cannot rely on that (if mystr is a variable instead of a literal) you should not use it.
So, it's generally dangerous -and conceptually wrong- to pass a dynamic string as single argument of printf...
How to send a simple string between two programs using pipes?
...lt;sys/types.h>
#include <unistd.h>
int main()
{
int fd;
char * myfifo = "/tmp/myfifo";
/* create the FIFO (named pipe) */
mkfifo(myfifo, 0666);
/* write "Hi" to the FIFO */
fd = open(myfifo, O_WRONLY);
write(fd, "Hi", sizeof("Hi"));
close(fd);
/* rem...
C++STL容器使用经验总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
...关联容器hash_set、hase_multiset、hash_map和hash_multimap。
vector<char> 作为string的替代。(见第13条)
vector作为标准关联容器的替代。(见第23条)
几种标准的非STL容器，包括数组、bitset、valarray、stack、queue和priority_queue。
你是否关心容器...
Maximum length for MySQL type text
...e to the max length of a text field in my MySQL database table. How many characters can a type text field store?
8 Answer...
How do I increase the RAM and set up host-only networking in Vagrant?
...nage-modifyvm
The vagrant documentation has the section on how to change IP address:
Vagrant::Config.run do |config|
config.vm.network :hostonly, "192.168.50.4"
end
Also you can restructure the configuration like this, ending is do with end without nesting it.
This is simpler.
config.vm.defi...
What are the mechanics of short string optimization in libc++?
...th:
1 bit goes to the long/short flag.
7 bits goes to the size.
Assuming char, 1 byte goes to the trailing null (libc++ will always store a trailing null behind the data).
This leaves 3 words minus 2 bytes to store a short string (i.e. largest capacity() without an allocation).
On a 32 bit mach...
Passing variable arguments to another function that accepts a variable argument list
...#include <stdio.h>
template<typename... Args> void test(const char * f, Args... args) {
printf(f, args...);
}
int main()
{
int a = 2;
test("%s\n", "test");
test("%s %d %d %p\n", "second test", 2, a, &a);
}
At the very least, it works with g++.
...
Why does appending “” to a String save memory?
...s that substring() gives a window onto an existing String - or rather, the character array underlying the original String. Hence it will consume the same memory as the original String. This can be advantageous in some circumstances, but problematic if you want to get a substring and dispose of the o...
When is CRC more appropriate to use than MD5/SHA1?
... inappropriate CRC hashes are for hash tables. It also explains the actual characteristics of the algorithm. The study also includes evaluation of other hash algorithms and is a good reference to keep.
The relevant conclusion on CRC for hashes:
CRC32 was never intended for hash table use. There...