Get the supplementary group IDs of the calling process
#include <sys/types.h> #include <unistd.h> int getgroups( int gidsetsize, gid_t grouplist[] );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The getgroups() function fills the array grouplist with the supplementary group IDs of the calling process. The values of array entries with indices greater than or equal to the returned value are undefined.
The number of supplementary groups IDs; this value is zero if NGROUPS_MAX is zero. A value of -1 indicates an error (errno is set).
/* * Print the supplementary group IDs of * the calling process. */ #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <unistd.h> int main( void ) { int gidsize; gid_t *grouplist; int i; gidsize = getgroups( 0, NULL ); grouplist = malloc( gidsize * sizeof( gid_t ) ); getgroups( gidsize, grouplist ); for( i = 0; i < gidsize; i++ ) printf( "%d\n", ( int ) grouplist[i] ); return EXIT_SUCCESS; }
Safety: | |
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Cancellation point | No |
Interrupt handler | No |
Signal handler | Yes |
Thread | Yes |
errno, getegid(), geteuid(), getgid(), getuid(), setgroups()