stat()返回错误

Question

我必须知道文件夹中某些文件的修改日期。它可以工作，但并不适用于所有类型的文件。例如，它适用于.c、.txt，但不适用于其他类型，如.mp4、.jpg和.mp3 (我正在创建的应用程序通常必须处理多媒体文件)。它输出"Cannot display the time."，所以我认为问题出在stat()上。谢谢。

代码如下：

#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>

char parola[12]="", hash[32]="", esadecimale[1000]="", system3[100]="./md5 ";
int i, len, len2;
int bytes;
char cwd[1024];

int main(void)
{
char t[100] = "";
struct stat b;
DIR *dp;
char destinationFolder[100] = "/Users/mattiazeni/Desktop/Prova/"; //Me la passa da sopra
struct dirent *dir_p;
dp = opendir(destinationFolder);
if ( dp == NULL ) exit(1);

len = strlen(destinationFolder);

for (i=0;i<len;i++) {
    system3[i+6]=destinationFolder[i];
}

while( ( dir_p = readdir(dp) ) != NULL ) {
    if (dir_p -> d_name[0] != '.') {
        //printf("%s\n", dir_p -> d_name);
        len2 = strlen(dir_p -> d_name);
        for (i=0;i<len2;i++) {
            if (dir_p -> d_name[i] == ' '){ //Mi serve per correggere i nomi dei file con spazi
                system3[i+len+6]='\\';   
            }
            else system3[i+len+6]=dir_p -> d_name[i];
        }
        system(system3); //Passa il valore a md5 che calcola l'hash e lo stampa nel file che ci serve insieme al persorso/nome del file

        FILE *fp;
        if((fp=fopen("userDatabase.txt", "ab"))==NULL) {
            printf("Error while opening the file..\n");
            fclose (fp);
        }
        else {
            if (!stat(dir_p -> d_name, &b)) {
            strftime(t, 100, "%d/%m/%Y %H:%M:%S", localtime( &b.st_mtime));         //C'è ancora qualche errore!!
            fprintf(fp, "%s", t);           
            }
            else {
                perror(0);
                fprintf(fp, "error");
            }
            fprintf(fp, " initialized");
            fprintf(fp, "\n");
        }
        fclose (fp);
        for (i=len+6;i<len+6+len2;i++) {
            system3[i]=' ';
        }
    }
}   
closedir(dp);
return 0;
}

Answer 1

您应该使用stat()的完整路径名。Stat不知道您感兴趣的是哪个目录。

... 
char  bigbuff[PATH_MAX];

sprintf( bigbuff, "%s/%s", destinationFolder, dir_p->d_name);

rc = stat (bigbuff, &b);
...

Answer 2

这是最终的工作代码，目的是扫描目录中的文件，并将它们打印在带有修改日期的txt输出文件上：

#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>

char system3[6]="./md5 ";

int main(void)
{
char t[100] = "";
char bigbuff[200];
struct stat b;
char destinationFolder[100] = "/Users/mattiazeni/Desktop/Prova"; //Me la passa da sopra
DIR *dp;
struct dirent *dir_p;
dp = opendir(destinationFolder);
if ( dp == NULL ) exit(1);
while( ( dir_p = readdir(dp) ) != NULL ) {
    if (dir_p -> d_name[0] != '.') {
        sprintf( bigbuff, "%s%s/%s",system3, destinationFolder, dir_p->d_name);
        system(bigbuff); 

        FILE *fp;
        if((fp=fopen("userDatabase.txt", "ab"))==NULL) {
            printf("Error while opening the file..\n");
            fclose (fp);
        }
        else {
            sprintf( bigbuff, "%s/%s", destinationFolder, dir_p->d_name);
            if (!stat(bigbuff, &b)) {
            strftime(t, 100, "%d/%m/%Y %H:%M:%S", localtime( &b.st_mtime));         //C'è ancora qualche errore!!
            fprintf(fp, "%s", t);           
            }
            else {
                perror(0);
                fprintf(fp, "error");
            }
            fprintf(fp, "\n");
        }
        fclose (fp);
    }
}   
closedir(dp);
return 0;
}

感谢大家的帮助！