C編程創建並寫入文件

Question

，我想我的程序執行以下操作：777 1）創造一個名爲FILENAME.TXT 2文件）分配權限）收件「這將是輸出到TESTFILE.TXT \ n「到新創建的文件

#include <stdio.h> 
#include <stdlib.h> 
#include <fcntl.h> 
#include <unistd.h> 
#include <sys/stat.h> 
#define PERMS 0777 

int main(int argc, char *argv[]) 
{ 

int createDescriptor; 
int openDescriptor; 

char fileName[15]="Filename.txt"; 

if ((openDescriptor = open(fileName, O_CREAT | O_WRONLY)) == -1) 
{ 
printf("Error creating %s\n", fileName); 
exit(EXIT_FAILURE); 
} 

umask(0000); 

if ((openDescriptor = creat(fileName, PERMS)) == -1) 
{ 
printf("Error creating %s", fileName); 
exit(EXIT_FAILURE); 
} 

if(write(openDescriptor,"This will be output to testfile.txt\n",36) != 36) 
{ 
write(2,"There was an error writing to testfile.txt\n",43); 
return 1; 
} 

if((close(openDescriptor))==-1) 
{ 
write(2, "Error closing file.\n", 19); 
} 

return 0; 
} 

Answer 1

你這樣做是錯誤的。

只需執行int openDescriptor = creat(fileName, PERMS);來創建並打開文件並將正確的權限。如果文件已經存在，該調用不會失敗。

最後，只寫：write(openDescriptor, ...);

爲了記錄在案，你不應該使用777文件模式。出於安全原因，不建議這樣做。