Linux下用C语言判断程序是否已运行

通过程序名获得进程号，然后和当前程序进程号做对比。

int isRunning()
{
int ret = 0;
char sCurrPid[16] = {0};
sprintf(sCurrPid, "%d\n", getpid());

FILE *fstream=NULL;
char buff[1024] = {0};

// a.out为你的可执行程序名
if(NULL==(fstream=popen("ps -aux | grep a.out | grep -v grep | awk '{print $2}'", "r")))
{
fprintf(stderr,"execute command failed: %s", strerror(errno));
return -1;
}
while(NULL!=fgets(buff, sizeof(buff), fstream)) {
if (strlen(buff) > 0) {
if (strcmp(buff, sCurrPid) !=0) {
printf("%s, %s\n", buff, sCurrPid);
ret = 1;
break;
}
}
}
pclose(fstream);

return ret;
}

另外一种兼容嵌入式设备。因为嵌入式设备可能没有awk命令，因此采用下面这个通用的方法。

char* getPidFromStr(const char *str)
{
static char sPID[8] = {0};
int tmp = 0;
int pos1 = 0;
int pos2 = 0;
int i = 0;
int j = 0;

for (i=0; i<strlen(str); i++) {
if ( (tmp==0) && (str[i]>='0' && str[i]<='9') ) {
tmp = 1;
pos1 = i;
}
if ( (tmp==1) && (str[i]<'0' || str[i]>'9') ) {
pos2 = i;
break;
}
}
for (j=0,i=pos1; i<pos2; i++,j++) {
sPID[j] = str[i];
}
return sPID;
}

int isRunning()
{
int ret = 0;
char sCurrPid[16] = {0};
sprintf(sCurrPid, "%d", getpid());

FILE *fstream=NULL;
char buff[1024] = {0};
if(NULL==(fstream=popen("ps -e -o pid,comm | grep a.out | grep -v PID | grep -v grep", "r")))
{
fprintf(stderr,"execute command failed: %s", strerror(errno));
return -1;
}
while(NULL!=fgets(buff, sizeof(buff), fstream)) {
char *oldPID = getPidFromStr(buff);
if ( strcmp(sCurrPid, oldPID) != 0 ) {
printf("程序已经运行，PID=%s\n", oldPID);
ret = 1;
}
}
pclose(fstream);

return ret;
}