[英]Fork/Dup2/Exec not working with mkstemp
為什么在以下程序中字數輸出0 0 0?
int main(int argc, char **argv) {
pid_t pid = fork();
const char *data = "THIS IS MY DATA.";
if(pid == 0) {
// Child Process
char *tmpname = malloc(15);
strcpy(tmpname, "/tmp/datXXXXXX");
int f = mkstemp(tmpname);
//int f = open("tmpfile", O_RDWR | O_CREAT, S_IRWXU);
if(f == -1) {
perror("");
return;
}
int written = write(f, data, strlen(data));
dup2(f, STDIN_FILENO);
close(f);
char *wcargs[5] = {"wc", NULL};
execvp("wc", wcargs);
fprintf(stderr, "ERROR");
}
return 1;
}
嘗試使用lseek(0,0,SEEK_SET)在dup2()之后倒回stdin。 在您的代碼中,wc將嘗試從文件末尾讀取,並且顯然不會讀取任何字節。
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