prefix

i++ less efficient than ++i, how to show this?

由 妖精的绣舞 提交于 2019-12-28 04:13:33
问题 I am trying to show by example that the prefix increment is more efficient than the postfix increment. In theory this makes sense: i++ needs to be able to return the unincremented original value and therefore store it, whereas ++i can return the incremented value without storing the previous value. But is there a good example to show this in practice? I tried the following code: int array[100]; int main() { for(int i = 0; i < sizeof(array)/sizeof(*array); i++) array[i] = 1; } I compiled it

i++ less efficient than ++i, how to show this?

由 你说的曾经没有我的故事 提交于 2019-12-28 04:13:31
问题 I am trying to show by example that the prefix increment is more efficient than the postfix increment. In theory this makes sense: i++ needs to be able to return the unincremented original value and therefore store it, whereas ++i can return the incremented value without storing the previous value. But is there a good example to show this in practice? I tried the following code: int array[100]; int main() { for(int i = 0; i < sizeof(array)/sizeof(*array); i++) array[i] = 1; } I compiled it

Linux下指定pip install和make install安装路径

由 霸气de小男生 提交于 2019-12-27 06:28:52
1. 在Linux下直接用pip install packageName，有些文件会被放到根目录下，如果没有sudo权限的话，是会安装失败的。这个以后我们就需要指定安装的目录了。 pip install --install-option="--prefix=绝对路径" packageName 2.一般编译源代码三部曲 ./configure make make install 这种默认安装路径的话，会把可执行文件拷贝到/usr/local/bin，如果没有sudo权限的话是会失败的，有两种方法指定安装路径。 a) 一种是在./configure的时候指定路径 ./configure --prefix=安装路径 b) 一种是make install的时候指定路径 make install DESTDIR=安装路径 1. 在Linux下直接用pip install packageName，有些文件会被放到根目录下，如果没有sudo权限的话，是会安装失败的。这个以后我们就需要指定安装的目录了。 pip install --install-option="--prefix=绝对路径" packageName 2.一般编译源代码三部曲 ./configure make make install 这种默认安装路径的话，会把可执行文件拷贝到/usr/local/bin

gdb 7.7 交叉编译

由 此生再无相见时 提交于 2019-12-27 06:11:13
1. 下载gdb，下载地址： http://www.sourceware.org/gdb/ 2. 准备编译过程需要的依赖库 termcap，下载地址： http://ftp.gnu.org/gnu/termcap/ 　　编译termcap： 　　$ mkdir /home/tom/tool/termcap　　 　　$ tar zxvf termcap-1.3.1.tar.gz 　　$ cd termcap-1.3.1 　　 　　$ ./configure --host=arm-none-linux-gnueabi --prefix=/home/tom/tool/termcap 　　$ vim Makefile 　　更改Makefile内容(这点很重要)： 　　CC = arm-none-linux-gnueabi-gcc 　　AR = arm-none-linux-gnueabi-ar 　　RANLIB = arm-none-linux-gnueabi-ranlib 　 　　$ make 　　$ make install 　　make install 将在 --prefix指定的目录/home/tom/tool/termcap中生成 include/termcap.h 和 lib/libtermcap.a， 编译gdb时需要指定对应的 库 和 头文件 搜索目录 3. 编译gdb 　

nginx离线安装安装

由 故事扮演 提交于 2019-12-26 00:39:53
1 --先安装PCRE作用是让Nginx支持重写功能。 下载PCRE安装包，下载地址： http://downloads.sourceforge.net/project/pcre/pcre/8.35/pcre-8.35.tar.gz http://www.pcre.org/ tar -zxvf pcre-8.38.tar.gz cd pcre-8.38 ./configure --prefix=/app/pcressl/pcre-8.38 #make && make install 报错：configure: error: You need a C++ compiler for C++ support 需要安装： yum install -y gcc gcc-c++ 2 --安装 openssl openssl-1.0.2n.tar 强大的安全套接字层密码库 tar -xvf openssl-1.0.2n.tar cd openssl-1.0.2n ./config --prefix=/app/pcressl/openssl-1.0.2n # make && make install 3.--安装zlib 为的是解包gzip http://www.zlib.net/ tar -xvf zlib-1.2.11.tar cd zlib-1.2.11 ./configure -

Prefix each parameter in a variadic macro that points to another macro

由 眉间皱痕 提交于 2019-12-25 16:39:53
问题 Let's assume that I have these macros that are prefixed with ATTRIB_ #define ATTRIB_A "a" #define ATTRIB_B "b" #define ATTRIB_C "c" I would like to be able to use a variadic macro that unpacks each given parameter then prefixes it with ATTRIB_ to obtain the full name of an attribute macro in order to expand that macro: #define ATTRIBS(...) CONFUSED_HERE(##__VA_ARGS__) Which would be used as: const char * a = ATTRIBS(A, B, C); And the result would be equal to: const char * a = "a" "b" "c"; As

prefix notation string to int conversion

由 孤人 提交于 2019-12-25 08:24:07
问题 I've been trying to think of a way to convert a string to an integer, I know the old atoi() in C and as well as the sstream function to convert a string type to a integer. I am trying to a write a program that that takes in a prefix notation and produces a result recursively. The program works, when I use char instead of string, but I am not really sure how I am suppose to use strings to solve this problem. I have to have it so that the user enter + 3 3 and result is 6. #include <iostream>

RegExp in ActionScript 3: How to exclude a complex prefix?

由 ￡可爱￡侵袭症＋ 提交于 2019-12-25 04:16:13
问题 AS3 RegExp engine (and ECMAScript based JavaScript) do not support complex "lookbehind" expressions. (lookahead expressions are fully supported.) For example: (?<=<body>)(.*?)(?=<\/body>) will work but; (?<=<body\b[^>]*>)(.*?)(?=<\/body>) will not work in AS3. What I need is to match a complex prefix but exclude it in the final match. In the example above; I'm trying to get the body contents in an HTML text but NOT the opening and closing body tags. And the actual test text looks like this:

Zend Framework 2 - Set prefix for form elements

由 给你一囗甜甜゛ 提交于 2019-12-25 02:52:22
问题 I'm looking for a way to add prefixes for every element of a certain form. If found this post telling me that there is a elementsBelongTo option which I can use to achieve what I want. Unfortunately I can't find any documentation explaining the usage. Does anyone know how I can use this option? And if it's still in ZF2? And furthermore: I there a way to combine it with the nice AnnotationForms ? 回答1: Don't know if it will help, but instead of prefix you can wrap elements in form or fieldset

Zend Framework 2 - Set prefix for form elements

由 試著忘記壹切 提交于 2019-12-25 02:52:06
问题 I'm looking for a way to add prefixes for every element of a certain form. If found this post telling me that there is a elementsBelongTo option which I can use to achieve what I want. Unfortunately I can't find any documentation explaining the usage. Does anyone know how I can use this option? And if it's still in ZF2? And furthermore: I there a way to combine it with the nice AnnotationForms ? 回答1: Don't know if it will help, but instead of prefix you can wrap elements in form or fieldset
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