ulimit(3p) [posix man page]
ULIMIT(3P) POSIX Programmer's Manual ULIMIT(3P) PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
ulimit -- get and set process limits SYNOPSIS
#include <ulimit.h> long ulimit(int cmd, ...); DESCRIPTION
The ulimit() function shall control process limits. The process limits that can be controlled by this function include the maximum size of a single file that can be written (this is equivalent to using setrlimit() with RLIMIT_FSIZE). The cmd values, defined in <ulimit.h>, include: UL_GETFSIZE Return the file size limit (RLIMIT_FSIZE) of the process. The limit shall be in units of 512-byte blocks and shall be inherited by child processes. Files of any size can be read. The return value shall be the integer part of the soft file size limit divided by 512. If the result cannot be represented as a long, the result is unspecified. UL_SETFSIZE Set the file size limit for output operations of the process to the value of the second argument, taken as a long, multiplied by 512. If the result would overflow an rlim_t, the actual value set is unspecified. Any process may decrease its own limit, but only a process with appropriate privileges may increase the limit. The return value shall be the integer part of the new file size limit divided by 512. The ulimit() function shall not change the setting of errno if successful. As all return values are permissible in a successful situation, an application wishing to check for error situations should set errno to 0, then call ulimit(), and, if it returns -1, check to see if errno is non-zero. RETURN VALUE
Upon successful completion, ulimit() shall return the value of the requested limit. Otherwise, -1 shall be returned and errno set to indi- cate the error. ERRORS
The ulimit() function shall fail and the limit shall be unchanged if: EINVAL The cmd argument is not valid. EPERM A process not having appropriate privileges attempts to increase its file size limit. The following sections are informative. EXAMPLES
None. APPLICATION USAGE
Since the ulimit() function uses type long rather than rlim_t, this function is not sufficient for file sizes on many current systems. Applications should use the getrlimit() or setrlimit() functions instead of the obsolescent ulimit() function. RATIONALE
None. FUTURE DIRECTIONS
The ulimit() function may be removed in a future version. SEE ALSO
exec, getrlimit(), write() The Base Definitions volume of POSIX.1-2008, <ulimit.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Stan- dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html . Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html . IEEE
/The Open Group 2013 ULIMIT(3P)
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ULIMIT(1P) POSIX Programmer's Manual ULIMIT(1P) PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
ulimit -- set or report file size limit SYNOPSIS
ulimit [-f] [blocks] DESCRIPTION
The ulimit utility shall set or report the file-size writing limit imposed on files written by the shell and its child processes (files of any size may be read). Only a process with appropriate privileges can increase the limit. OPTIONS
The ulimit utility shall conform to the Base Definitions volume of POSIX.1-2008, Section 12.2, Utility Syntax Guidelines. The following option shall be supported: -f Set (or report, if no blocks operand is present), the file size limit in blocks. The -f option shall also be the default case. OPERANDS
The following operand shall be supported: blocks The number of 512-byte blocks to use as the new file size limit. STDIN
Not used. INPUT FILES
None. ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of ulimit: LANG Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume of POSIX.1-2008, Section 8.2, Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.) LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables. LC_CTYPE Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi-byte characters in arguments). LC_MESSAGES Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error. NLSPATH Determine the location of message catalogs for the processing of LC_MESSAGES. ASYNCHRONOUS EVENTS
Default. STDOUT
The standard output shall be used when no blocks operand is present. If the current number of blocks is limited, the number of blocks in the current limit shall be written in the following format: "%d ", <number of 512-byte blocks> If there is no current limit on the number of blocks, in the POSIX locale the following format shall be used: "unlimited " STDERR
The standard error shall be used only for diagnostic messages. OUTPUT FILES
None. EXTENDED DESCRIPTION
None. EXIT STATUS
The following exit values shall be returned: 0 Successful completion. >0 A request for a higher limit was rejected or an error occurred. CONSEQUENCES OF ERRORS
Default. The following sections are informative. APPLICATION USAGE
Since ulimit affects the current shell execution environment, it is always provided as a shell regular built-in. If it is called in a sepa- rate utility execution environment, such as one of the following: nohup ulimit -f 10000 env ulimit 10000 it does not affect the file size limit of the caller's environment. Once a limit has been decreased by a process, it cannot be increased (unless appropriate privileges are involved), even back to the origi- nal system limit. EXAMPLES
Set the file size limit to 51200 bytes: ulimit -f 100 RATIONALE
None. FUTURE DIRECTIONS
None. SEE ALSO
The Base Definitions volume of POSIX.1-2008, Chapter 8, Environment Variables, Section 12.2, Utility Syntax Guidelines The System Interfaces volume of POSIX.1-2008, ulimit() COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Stan- dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html . Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html . IEEE
/The Open Group 2013 ULIMIT(1P)