exec一共有六種函數，都是以exec開頭。

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1 int execl(const char *path, const char *arg, ...); 2 int execlp(const char *file, const char *arg, ...); 3 int execle(const char *path, const char *arg, ..., char * const envp[]); 4 int execv(const char *path, char *const argv[]); 5 int execvp(const char *file, char *const argv[]); 6 int execve(const char *path, char *const argv[], char *const envp[]);

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后綴	含義
l	l代表list,接受以逗號的參數，最后是以(char *)0結束。
v	v代表vector,接受參數數組，數組以NULL結束。
p	p代表取用PATH環境環境尋找可執行文件，不需要單獨傳入一個路徑參數。
e	取代當前的環境環境

主程序

1 #include <stdio.h> 2 #include <unistd.h> 3 #include <sys/wait.h> 4 #include <errno.h> 5 extern char **environ; 6 int main(){ 7 char *env[]={"USER=hh","PATH=/home/map/users",NULL}; 8 int pid; 9 if((pid=fork())<0){ 10 perror("fork error;"); 11 }else if(pid==0){ 12 execle("/home/map/users/maxin/cpp/chr08/test","test","hello","world",(char *)0,env); 13 perror("exec error:"); 14 } 15 if(waitpid(pid,NULL,0)!=pid){ 16 perror("wait error"); 17 } 18 printf("----------------------------------------\n"); 19 if((pid=fork())<0){ 20 perror("fork error;"); 21 }else if(pid==0){ 22 execle("/home/map/users/maxin/cpp/chr08/test","test","hello","world",(char *)0,environ); 23 perror("exec error:"); 24 } 25 if(waitpid(pid,NULL,0)!=pid){ 26 perror("wait error"); 27 } 28 29 printf("----------------------------------------\n"); 30 if((pid=fork())<0){ 31 perror("fork error;"); 32 }else if(pid==0){ 33 execlp("./test","./test","hello",(char *)0); 34 perror("exec error:"); 35 } 36 if(waitpid(pid,NULL,0)!=pid){ 37 perror("wait error"); 38 } 39 }

被調用的程序

1 #include <stdio.h> 2 #include <stdlib.h> 3 extern char **environ; 4 void showEnv(); 5 int main(int args,const char *argv[]){ 6 printf("args%d\n",args ); 7 for(int i=0;i!=args;++i){ 8 printf("argv[%d]:%s\n",i,argv[i]); 9 } 10 printf("USER:%s\n", getenv("USER")); 11 printf("PATH:%s\n", getenv("PATH")); 12 showEnv(); 13 } 14 void showEnv(){ 15 int i=0; 16 while(environ[i]){ 17 printf("environ[%d]:%s\n",i,environ[i] ); 18 ++i; 19 } 20 printf("----------------------END---------------------------\n" ); 21 }

?最后的顯示結果

args3 argv[0]:test argv[1]:hello argv[2]:world USER:hh PATH:/home/map/users environ[0]:USER=hh environ[1]:PATH=/home/map/users ----------------------END--------------------------- ---------------------------------------- args3 argv[0]:test argv[1]:hello argv[2]:world USER:map PATH:/home/tools/tools/svn/1.6.5/64/bin:/home/tools/tools/scmtools/usr/bin:/home/tools/tools/../bin/64/:/home/tools/tools/maven/apache-maven-2.2.0/bin:/home/tools/tools/ant/apache-ant-1.6.5/bin:/home/tools/tools/ant/apache-ant-1.7.1/bin:/home/tools/tools/php/5.2.17/64/bin:/java/jdk1.6.0_06/bin:/java/jdk1.6.0_06/jre/bin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/usr/share/*****/bin:/opt/bin:/home/opt/bin:/home/map/bin:/home/work/.nlpcloud/nlpc/bin:/home/work/.qu/qu:/home/map/bin:/home/map/users/yinsongyang/fis/node-v0.10.26-linux-x64/bin:/home/map/users/yinsongyang/fis/jre1.7.0_55/bin:/home/map/odp24/php/bin environ[0]:MAC=64 environ[1]:MANPATH=:/tools/*****_manpage/man environ[2]:HOSTNAME=cq01-rdqa-*****.*****.*****.com environ[3]:TERM=vt100 environ[4]:SHELL=/bin/bash environ[5]:HISTSIZE=1000 environ[6]:SSH_CLIENT=172.22.4.13 36038 22 environ[7]:OLDPWD=/home/map/users/maxin/cpp environ[8]:MAVEN_2_2_1=/home/tools/tools/maven/apache-maven-2.2.1/bin environ[9]:SSH_TTY=/dev/pts/2 environ[10]:MAVEN_3_0_4=/home/tools/tools/maven/apache-maven-3.0.4/bin environ[11]:ANT_HOME=/home/tools/tools/ant/apache-ant-1.6.5 environ[12]:USER=map environ[13]:LS_COLORS=no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:*.xpm=01;35:*.png=01;35:*.tif=01;35: environ[14]:MAIL=/var/spool/mail/map environ[15]:PATH=/home/tools/tools/svn/1.6.5/64/bin:/home/tools/tools/scmtools/usr/bin:/home/tools/tools/../bin/64/:/home/tools/tools/maven/apache-maven-2.2.0/bin:/home/tools/tools/ant/apache-ant-1.6.5/bin:/home/tools/tools/ant/apache-ant-1.7.1/bin:/home/tools/tools/php/5.2.17/64/bin:/java/jdk1.6.0_06/bin:/java/jdk1.6.0_06/jre/bin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/usr/share/*****/bin:/opt/bin:/home/opt/bin:/home/map/bin:/home/work/.nlpcloud/nlpc/bin:/home/work/.qu/qu:/home/map/bin:/home/map/users/yinsongyang/fis/node-v0.10.26-linux-x64/bin:/home/map/users/yinsongyang/fis/jre1.7.0_55/bin:/home/map/odp24/php/bin environ[16]:INPUTRC=/etc/inputrc environ[17]:PWD=/home/map/users/maxin/cpp/chr08 environ[18]:JAVA_HOME=/java/jdk1.6.0_06 environ[19]:LANG=en_US environ[20]:JAVA_HOME_1_6=/home/tools/tools/java/jdk1.6.0_20 environ[21]:JAVA_HOME_1_5=/home/tools/tools/java/jdk1.5.0_07 environ[22]:ANT_HOME_1_7=/home/tools/tools/ant/apache-ant-1.7.1 environ[23]:SHLVL=1 environ[24]:HOME=/home/map environ[25]:LOGNAME=map environ[26]:CLASSPATH=:/java/jdk1.6.0_06/lib:/java/jdk1.6.0_06/jre/lib environ[27]:SSH_CONNECTION=172.22.4.13 36038 10.48.52.44 22 environ[28]:PKG_CONFIG_PATH=/usr/local/lib/pkgconfig: environ[29]:LESSOPEN=|/usr/bin/lesspipe.sh %s environ[30]:G_BROKEN_FILENAMES=1 environ[31]:_=./a.out ----------------------END--------------------------- ---------------------------------------- args2 argv[0]:./test argv[1]:hello USER:map PATH:/home/tools/tools/svn/1.6.5/64/bin:/home/tools/tools/scmtools/usr/bin:/home/tools/tools/../bin/64/:/home/tools/tools/maven/apache-maven-2.2.0/bin:/home/tools/tools/ant/apache-ant-1.6.5/bin:/home/tools/tools/ant/apache-ant-1.7.1/bin:/home/tools/tools/php/5.2.17/64/bin:/java/jdk1.6.0_06/bin:/java/jdk1.6.0_06/jre/bin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/usr/share/*****/bin:/opt/bin:/home/opt/bin:/home/map/bin:/home/work/.nlpcloud/nlpc/bin:/home/work/.qu/qu:/home/map/bin:/home/map/users/yinsongyang/fis/node-v0.10.26-linux-x64/bin:/home/map/users/yinsongyang/fis/jre1.7.0_55/bin:/home/map/odp24/php/bin environ[0]:MAC=64 environ[1]:MANPATH=:/tools/*****_manpage/man environ[2]:HOSTNAME=cq01-rdqa-*****.*****.*****.com environ[3]:TERM=vt100 environ[4]:SHELL=/bin/bash environ[5]:HISTSIZE=1000 environ[6]:SSH_CLIENT=172.22.4.13 36038 22 environ[7]:OLDPWD=/home/map/users/maxin/cpp environ[8]:MAVEN_2_2_1=/home/tools/tools/maven/apache-maven-2.2.1/bin environ[9]:SSH_TTY=/dev/pts/2 environ[10]:MAVEN_3_0_4=/home/tools/tools/maven/apache-maven-3.0.4/bin environ[11]:ANT_HOME=/home/tools/tools/ant/apache-ant-1.6.5 environ[12]:USER=map environ[13]:LS_COLORS=no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:*.xpm=01;35:*.png=01;35:*.tif=01;35: environ[14]:MAIL=/var/spool/mail/map environ[15]:PATH=/home/tools/tools/svn/1.6.5/64/bin:/home/tools/tools/scmtools/usr/bin:/home/tools/tools/../bin/64/:/home/tools/tools/maven/apache-maven-2.2.0/bin:/home/tools/tools/ant/apache-ant-1.6.5/bin:/home/tools/tools/ant/apache-ant-1.7.1/bin:/home/tools/tools/php/5.2.17/64/bin:/java/jdk1.6.0_06/bin:/java/jdk1.6.0_06/jre/bin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/usr/share/*****/bin:/opt/bin:/home/opt/bin:/home/map/bin:/home/work/.nlpcloud/nlpc/bin:/home/work/.qu/qu:/home/map/bin:/home/map/users/yinsongyang/fis/node-v0.10.26-linux-x64/bin:/home/map/users/yinsongyang/fis/jre1.7.0_55/bin:/home/map/odp24/php/bin environ[16]:INPUTRC=/etc/inputrc environ[17]:PWD=/home/map/users/maxin/cpp/chr08 environ[18]:JAVA_HOME=/java/jdk1.6.0_06 environ[19]:LANG=en_US environ[20]:JAVA_HOME_1_6=/home/tools/tools/java/jdk1.6.0_20 environ[21]:JAVA_HOME_1_5=/home/tools/tools/java/jdk1.5.0_07 environ[22]:ANT_HOME_1_7=/home/tools/tools/ant/apache-ant-1.7.1 environ[23]:SHLVL=1 environ[24]:HOME=/home/map environ[25]:LOGNAME=map environ[26]:CLASSPATH=:/java/jdk1.6.0_06/lib:/java/jdk1.6.0_06/jre/lib environ[27]:SSH_CONNECTION=172.22.4.13 36038 10.48.52.44 22 environ[28]:PKG_CONFIG_PATH=/usr/local/lib/pkgconfig: environ[29]:LESSOPEN=|/usr/bin/lesspipe.sh %s environ[30]:G_BROKEN_FILENAMES=1 environ[31]:_=./a.out ----------------------END---------------------------

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轉載于:https://www.cnblogs.com/HPhone/p/3870046.html

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