getegid()--Get Effective Group ID

 #include <unistd.h>

 gid_t getegid(void);  

The getegid() function returns the effective group ID (GID) of the calling thread. The effective GID is the group ID under which the thread is currently running. The effective GID of a thread may change while the thread is running.

Parameters

None.

Authorities

No authorization is required.

Return Value

> 0

getegid() was successful. The value returned represents the effective GID.

>= 0

getegid() was successful. If there is no GID, the user ID has no group profile associated with it and returns 0. Otherwise, if there is a group profile, the API returns the GID of the group profile.

-1

getegid() was not successful. The errno global variable is set to indicate the error.

Error Conditions

If getegid() is not successful, errno usually indicates one of the following errors. Under some conditions, errno could indicate an error other than those listed here.

Related Information

• The <unistd.h> file (see Header Files for UNIX-Type Functions)

Example

See Code disclaimer information for information pertaining to code examples.

The following example gets the effective GID.

#include <unistd.h>

main()
{
  gid_t ef_gid;

  if (-1 == (ef_gid = getegid(void)))
     perror("getegid() error.");
  else
     printf("The effective GID is: %u\n", ef_gid);

}

Output:

  The effective GID is: 75