opendarwin man page for issetugid

ISSETUGID(2)						      BSD System Calls Manual						      ISSETUGID(2)

NAME
     issetugid -- is current executable running setuid or setgid

SYNOPSIS
     #include <unistd.h>

     int
     issetugid(void);

DESCRIPTION
     The issetugid() function returns 1 if the process was made setuid or setgid as the result of the last execve() system call.  Otherwise it
     returns 0.

     This system call exists so that library routines (inside libc, libtermlib, or other libraries) can gaurantee safe behavior when used inside
     setuid or setgid programs.  Some library routines may not be passed sufficient information to know if the current program was started setuid
     or setgid because higher level calling code may have made changes to the uid or the euid.	In particular, it is wise to use this call to
     determine if a pathname returned from a getenv() call may safely be used to open() the specified file.

     issetugid() is unaffected by calls to setuid(), fork(), and other such calls.  It is only controlled by execve().

ERRORS
     The issetugid() function is always successful, and no return value is reserved to indicate an error.

SEE ALSO
     execve(2), setuid(2), seteuid(2,) setgid(2), setegid(2)

HISTORY
     A lstat() function call appeared in OpenBSD 2.0

OpenBSD 2.0							  August, 25 1996						       OpenBSD 2.0