NAME

ulimit − get and set user limits

SYNOPSIS

long ulimit (cmd, newlimit)
int cmd;
long newlimit;

DESCRIPTION

This function provides for control over process limits.  The cmd values available are:

1 Get the regular file size limit of the process.  The limit is in units of 512-byte blocks and is inherited by child processes.  Files of any size can be read. 

2 Set the regular file size limit of the process to the value of newlimit. Any process may decrease this limit, but only a process with an effective user ID of super-user may increase the limit.  ulimit fails and the limit is unchanged if a process with an effective user ID other than super-user attempts to increase its regular file size limit.  ­[EPERM]

3 Get the maximum possible break value [see brk(2)].

4 Get the maximum number of open files limit.  This is a system-configured value. 

SEE ALSO

brk(2), write(2). 

WARNING

ulimit is effective in limiting the growth of regular files.  Pipes are currently limited to 5,120 bytes. 

DIAGNOSTICS

Upon successful completion, a non-negative value is returned.  Otherwise, a value of −1 is returned and errno is set to indicate the error. 

March 13, 1992