小编Sam*_*een的帖子

我是Android新手,我按照http://marakana.com/forums/android/examples/49.html链接上的说明使用NDK创建基本应用程序.

我完全按照这些步骤.我还创建了共享库.当我运行应用程序时,CatLog显示以下错误:

Trying to load lib /data/data/com.example.NDKDemo/lib/libndk_demo.so 0x4129dc18
01-30 04:50:58.856: D/dalvikvm(586): Added shared lib
                    /data/data/com.example.NDKDemo/lib/libndk_demo.so 0x4129dc18
01-30 04:50:58.856: D/dalvikvm(586): No JNI_OnLoad found in 
                    /data/data/com.example.NDKDemo/lib/libndk_demo.so 0x4129dc18,
                    skipping init
01-30 04:50:58.866: D/AndroidRuntime(586): Shutting down VM
01-30 04:50:58.866: W/dalvikvm(586): threadid=1: thread exiting with uncaught 
                    exception (group=0x409c01f8)
01-30 04:50:58.896: E/AndroidRuntime(586): FATAL EXCEPTION: main
01-30 04:50:58.896: E/AndroidRuntime(586): java.lang.RuntimeException:
                    Unable to instantiate activity ComponentInfo
                    {com.example.NDKDemo/com.example.NDKDemo.NativeLib}:
                    java.lang.ClassCastException:
                    com.example.NDKDemo.NativeLib cannot be cast to android.app.Activity

使用android-ndk-r7b/samples/hello-jni作为调试起点,我用jni构建了jni

ndk-build V = 1 NDK_DEBUG = 1

rm -f ./libs/armeabi/lib*.so ./libs/armeabi-v7a/lib*.so ./libs/x86/lib*.so
rm -f ./libs/armeabi/gdbserver ./libs/armeabi-v7a/gdbserver ./libs/x86/gdbserver
rm -f ./libs/armeabi/gdb.setup ./libs/armeabi-v7a/gdb.setup ./libs/x86/gdb.setup
Gdbserver      : [arm-linux-androideabi-4.4.3] libs/armeabi/gdbserver
mkdir -p ./libs/armeabi
install -p /cygdrive/c/Users/pcarreir/android-ndk-r7b/toolchains/arm-linux-androideabi-4.4.3/prebuilt/gdbserver ./libs/armeabi/gdbserver
Gdbsetup       : libs/armeabi/gdb.setup
mkdir -p ./libs/armeabi
/cygdrive/c/Users/pcarreir/android-ndk-r7b/prebuilt/windows/bin/echo "set solib-search-path ./obj/local/armeabi" > ./libs/armeabi/gdb.setup
/cygdrive/c/Users/pcarreir/android-ndk-r7b/prebuilt/windows/bin/echo "directory C:/Users/pcarreir/android-ndk-r7b/platforms/android-8/arch-arm/usr/include jni C:/Users/pcarreir/android-ndk-r7b/sources/cxx-stl/system" >> ./libs/armeabi/gdb.setup
Cygwin         : Generating dependency file converter script
mkdir -p obj/
mount | awk -f /cygdrive/c/Users/pcarreir/android-ndk-r7b/build/awk/gen-cygwin-deps-converter.awk > obj/convert-dependencies.sh && chmod +x obj/convert-dependencies.sh
Compile thumb  : hello-jni <= hello-jni.c …

我有一个几乎完全空白的data.frame,但每行都有一个值.如何使用矢量化或其他r-locald方法将每行的内容合并为一个向量？

样本数据:

raw_data  <- structure(
    list(
        col1 = c("", "", "", "", ""),
        col2 = c("", "", "", "", ""),
        col3 = c("", "", "", "", ""),
        col4 = c("", "", "", "Millburn - Union", ""),
        col5 = c("", "", "Cranston (aka Garden City Center)", "",""),
        col6 = c("", "", "", "", ""),
        col7 = c("", "", "", "", ""),
        col8 = c("", "", "", "", "Colorado Blvd"), 
        col9 = c("", "", "", "", ""),
        col10 = c("", "", "", …

按照我的理解，

free() 用于释放我们之前使用 malloc 分配的内存。

在下面的代码片段中，我释放了分配的内存。但是即使在释放后我也能够访问指针？怎么可能？

免费在内部如何运作？

#include<iostream>
using namespace std;

int main()
{
   int *p=(int *)malloc(sizeof(int));
   *p=17;
   free(p);
   *p=*p+1;
   printf("\n After freeing memory :: %d ",*p );
   return 0;
}

我是bash脚本的新手.我尝试了以下方法:

filename01 = ''

if [ $# -eq 0 ]
        then
                filename01 = 'newList01.txt'
        else
                filename01 = $1
fi

我收到以下错误:

./smallScript02.sh: line 9: filename01: command not found
./smallScript02.sh: line 13: filename01: command not found

我想我没有正确对待变量,但我不知道如何.此外,我试图使用grep从文本文件中提取第二个和第三个单词.该文件看起来像:

1966 Bart Starr QB Green Bay Packers 
1967 Johnny Unitas QB Baltimore Colts 
1968 Earl Morrall QB Baltimore Colts 
1969 Roman Gabriel QB Los Angeles Rams 
1970 John Brodie QB San Francisco 49ers 
1971 Alan Page DT Minnesota Vikings 
1972 Larry Brown RB Washington Redskins …

这是一个非常简短的问题.但是$example在bash文件中将变量作为tar的参数放置是否存在语法错误？

我把文件写成了

//only portion that really matters
#!/bin/bash
...
tar -cvpzf $filename $backup_source

//here's the actual code
#!/bin/bash
backup_source="~/momobobo"
backup_dest="~/momobobo_backup/"
dater=`date '+%m-%d-%Y-%H-%M-%S'`
filename="$backup_dest$dater.tgz"
echo “Backing Up your Linux System”
tar -cvpzf $filename $backup_source
echo tar -cvpzf $filename $backup_source
echo “Backup finished”

//and heres the error
“Backing Up your Linux System”
tar: ~/momobobo: Cannot stat: No such file or directory
tar (child): ~/momobobo_backup/07-02-2013-18-34-12.tgz: Cannot open: No such file or directory
tar   (child): Error is not recoverable: exiting now
tar: …

我有一个非常小的期望脚本.流程如下

1. ssh 到远程机器
2. 执行命令并在执行命令后,您将处于不同的提示符(提示名称为Enter cmd>.
3. 在Enter cmd>提示符下,我需要运行许多命令

因此我设计了这个脚本

#!/usr/bin/expect

 set FULL_CMD { #cmd1 #cmd2 #cmd3  }
 puts "STARTING......."

 log_file myfile.log ;# <<< === append output to a file
 spawn ssh tempuser\@dummyserver
 match_max  100000000

 expect "password:"
 send "temppasswd\r"
expect  "*temp*"
 send "cd \/home\r"
 expect "*temp*"
send "new cmd prompt\r"
expect "Enter cmd>"

foreach tempcmd $FULL_CMD {
 send "${tempcmd} \r "
 expect -exact  "Enter cmd>\r"
 send -- "\r"
expect eof }

send "q"
send "exit\r"

puts "I HAVE …