我想使用fgets而不是fscanf来获取stdin并通过管道将其发送给子进程。下面的代码工作排序的文件中的行但如何使用fgets()而不是fscanf()在标准输入C中?
fgets(word, 5000, stdin)
更换
fscanf(stdin, "%s", word)
给我的警告
warning: comparison between pointer and integer [enabled by default]
否则程序似乎工作。任何想法,为什么我得到警告?
int main(int argc, char *argv[])
{
pid_t sortPid;
int status;
FILE *writeToChild;
char word[5000];
int count = 1;
int sortFds[2];
pipe(sortFds);
switch (sortPid = fork()) {
case 0: //this is the child process
close(sortFds[1]); //close the write end of the pipe
dup(sortFds[0]);
close(sortFds[0]);
execl("/usr/bin/sort", "sort", (char *) 0);
perror("execl of sort failed");
exit(EXIT_FAILURE);
case -1: //failure to fork case
perror("Could not create child");
exit(EXIT_FAILURE);
default: //this is the parent process
close(sortFds[0]); //close the read end of the pipe
writeToChild = fdopen(sortFds[1], "w");
break;
}
if (writeToChild != 0) { //do this if you are the parent
while (fscanf(stdin, "%s", word) != EOF) {
fprintf(writeToChild, "%s %d\n", word, count);
}
}
fclose(writeToChild);
wait(&status);
return 0;
}