1、2
#include <stdio.h>#include <unistd.h>int main(){ char *arglist[3]; arglist[0] = "ls"; arglist[1] = "-l"; arglist[2] = 0 ;//NULL printf("* * * About to exec ls -l\n"); execvp( "ls" , arglist ); printf("* * * ls is done. bye"); return 0;}
3
#include <stdio.h>#include <unistd.h>int main(){ char *arglist[3]; char*myenv[3]; myenv[0] = "PATH=:/bin:"; myenv[1] = NULL; arglist[0] = "ls"; arglist[1] = "-l"; arglist[2] = 0 ; printf("* * * About to exec ls -l\n"); execlp("ls", "ls", "-l", NULL); printf("* * * ls is done. bye\n");}
4
#include <stdio.h>#include<sys/types.h>#include<unistd.h>int main(){ int ret_from_fork, mypid; mypid = getpid(); printf("Before: my pid is %d\n", mypid); ret_from_fork = fork(); sleep(1); printf("After: my pid is %d, fork() said %d\n", getpid(), ret_from_fork); return 0;}
5
#include <stdio.h>#include <unistd.h>int main(){ printf("before:my pid is %d\n", getpid() ); fork(); fork(); printf("aftre:my pid is %d\n", getpid() ); return 0;}
6
#include <stdio.h>#include <stdlib.h>#include <unistd.h>int main(){ int fork_rv; printf("Before: my pid is %d\n", getpid()); fork_rv = fork(); /* create new process */ if ( fork_rv == -1 ) /* check for error */ perror("fork"); else if ( fork_rv == 0 ){ printf("I am the child. my pid=%d\n", getpid()); exit(0); } else{ printf("I am the parent. my child is %d\n", fork_rv); exit(0); } return 0;}
7
#include <stdio.h>#include <stdlib.h>#include <unistd.h>int main(){ int fork_rv; printf("Before: my pid is %d\n", getpid()); fork_rv = fork(); /* create new process */ if ( fork_rv == -1 ) /* check for error */ perror("fork"); else if ( fork_rv == 0 ){ printf("I am the child. my pid=%d\n", getpid()); printf("parent pid= %d, my pid=%d\n", getppid(), getpid()); exit(0); } else{ printf("I am the parent. my child is %d\n", fork_rv); sleep(10); exit(0); } return 0;}
8
#include <stdio.h>#include <stdlib.h>#include <unistd.h>int gi=0;int main(){ int li=0; static int si=0; int i=0; pid_t pid = fork(); if(pid == -1){ exit(-1); } else if(pid == 0){ for(i=0; i<5; i++){ printf("child li:%d\n", li++); sleep(1); printf("child gi:%d\n", gi++); printf("child si:%d\n", si++); } exit(0); } else{ for(i=0; i<5; i++){ printf("parent li:%d\n", li++); printf("parent gi:%d\n", gi++); sleep(1); printf("parent si:%d\n", si++); } exit(0); } return 0;}
9
#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#define MAXARGS 20 #define ARGLEN 100 int execute( char *arglist[] ){ execvp(arglist[0], arglist); perror("execvp failed"); exit(1);}char * makestring( char *buf ){ char *cp; buf[strlen(buf)-1] = '\0'; cp = malloc( strlen(buf)+1 ); if ( cp == NULL ){ fprintf(stderr,"no memory\n"); exit(1); } strcpy(cp, buf); return cp; }int main(){ char *arglist[MAXARGS+1]; int numargs; char argbuf[ARGLEN]; numargs = 0; while ( numargs < MAXARGS ) { printf("Arg[%d]? ", numargs); if ( fgets(argbuf, ARGLEN, stdin) && *argbuf != '\n' ) arglist[numargs++] = makestring(argbuf); else { if ( numargs > 0 ){ arglist[numargs]=NULL; execute( arglist ); numargs = 0; } } } return 0;}
10
#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/wait.h>#include <unistd.h>#include <signal.h>#define MAXARGS 20 #define ARGLEN 100 char *makestring( char *buf ){ char *cp; buf[strlen(buf)-1] = '\0'; cp = malloc( strlen(buf)+1 ); if ( cp == NULL ){ fprintf(stderr,"no memory\n"); exit(1); } strcpy(cp, buf); return cp; }void execute( char *arglist[] ){ int pid,exitstatus; pid = fork(); switch( pid ){ case -1: perror("fork failed"); exit(1); case 0: execvp(arglist[0], arglist); perror("execvp failed"); exit(1); default: while( wait(&exitstatus) != pid ) ; printf("child exited with status %d,%d\n", exitstatus>>8, exitstatus&0377); }}int main(){ char *arglist[MAXARGS+1]; int numargs; char argbuf[ARGLEN]; numargs = 0; while ( numargs < MAXARGS ) { printf("Arg[%d]? ", numargs); if ( fgets(argbuf, ARGLEN, stdin) && *argbuf != '\n' ) arglist[numargs++] = makestring(argbuf); else { if ( numargs > 0 ){ arglist[numargs]=NULL; execute( arglist ); numargs = 0; } } } return 0;}
1
#include <stdio.h>#include <stdlib.h>int main(){ printf("hello"); fflush(stdout); while(1);}
2
#include <stdio.h>int main(){ printf("hello\n"); while(1);}
3
#include <stdio.h>int main(){ fprintf(stdout, "1234", 5); fprintf(stderr, "abcd", 4);}
4
#include <stdio.h>#include <unistd.h>#include <sys/types.h>int main(){ printf("my pid: %d \n", getpid()); printf("my parent's pid: %d \n", getppid()); return 0;}
5
#include <stdio.h>#include <stdlib.h>int main(){ char **pp; pp[0] = malloc(20); return 0;}
6
#include <stdlib.h>int main ( int argc, char *argv[] ){ system(argv[1]); system(argv[2]); return EXIT_SUCCESS;} /* ---------- end of function main ---------- */
7
#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/wait.h>#include <unistd.h>#define DELAY 4void child_code(int delay){ printf("child %d here. will sleep for %d seconds\n", getpid(), delay); sleep(delay); printf("child done. about to exit\n"); exit(17);}void parent_code(int childpid){ int wait_rv=0; /* return value from wait() */ wait_rv = wait(NULL); printf("done waiting for %d. Wait returned: %d\n", childpid, wait_rv);}int main(){ int newpid; printf("before: mypid is %d\n", getpid()); if ( (newpid = fork()) == -1 ) perror("fork"); else if ( newpid == 0 ) child_code(DELAY); else parent_code(newpid); return 0;}
#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/wait.h>#include <unistd.h>#define DELAY 10void child_code(int delay){ printf("child %d here. will sleep for %d seconds\n", getpid(), delay); sleep(delay); printf("child done. about to exit\n"); exit(27);}void parent_code(int childpid){ int wait_rv; int child_status; int high_8, low_7, bit_7; wait_rv = wait(&child_status); printf("done waiting for %d. Wait returned: %d\n", childpid, wait_rv); high_8 = child_status >> 8; /* 1111 1111 0000 0000 */ low_7 = child_status & 0x7F; /* 0000 0000 0111 1111 */ bit_7 = child_status & 0x80; /* 0000 0000 1000 0000 */ printf("status: exit=%d, sig=%d, core=%d\n", high_8, low_7, bit_7);}int main(){ int newpid; printf("before: mypid is %d\n", getpid()); if ( (newpid = fork()) == -1 ) perror("fork"); else if ( newpid == 0 ) child_code(DELAY); else parent_code(newpid);}
转载于:https://www.cnblogs.com/KG35/p/5005132.html
