chmod

raw OCR

Changes file access mode.

Defined in header <sys/stat.h>

Syntax

#include <sys\stat.h>
int chmod(const  char *path, int amode);

Portability

DOS	UNIX	Windows	ANSI C	C++ only
■	■	■

Remarks

chmod sets the file-access permissions of the file given by path according to the mask given by amode. path points to a string; *path is the first character of that string.

amode can contain one or both of the symbolic constants S_IWRITE and

SJREAD	(defined in sysXstat.h).

Value of amode	Access permission
SJWRITE	Permission to write
SJREAD	Permission to read
S IREADIS IWRITE	Permission to read and write

Return value

Upon successfully changing the file access mode, chmod returns 0. Otherwise, chmod returns a value of -1.

In the event of an error, the global variable errno is set to one of the following:

ENOENT Path or file name not found EACCES Permission denied

Example

#include <errno.h>
#include <stdio.h>
#include <io.h>
#include <process.h>
#include <sys\stat.h>
int main(void)
{
   char filename [64];
   struct Stat stbuf;
   int amode;
   printf("Enter name of  file: ");
   scanf("%s", filename);
   if (stat (filename, &stbuf) != 0) {
     perror("Unable to get  file information");
     return (1);
   }
   if (stbuf.st_mode & S_IWRITE)  {
     printf("Changing to read-only\n") ;
     amode = S_IREAD;

   else {
     printf("Changing to read-write\n") ;
     amode = S_IREADiS_IWRITE;
   }
   if (chmod (filename, amode) != 0) {
     perror ("Unable to change file mode");
     return(1);
   }
   return(0);

Differences from modern implementations

Nothing recorded yet.

Modern references

These are search links, not yet checked by hand.

Stable link: /3.1/sys/stat.h/chmod/ · short form /3.1/chmod/