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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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ULIMIT(3P) POSIX Programmer's Manual ULIMIT(3P)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
ulimit — get and set process limits
#include <ulimit.h>
long ulimit(int cmd, ...);
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.
Upon successful completion, ulimit() shall return the value of
the requested limit. Otherwise, -1 shall be returned and errno
set to indicate the error.
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.
None.
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.
None.
The ulimit() function may be removed in a future version.
exec(1p), getrlimit(3p), write(3p)
The Base Definitions volume of POSIX.1‐2017, ulimit.h(0p)
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. 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
Standard is the referee document. The original Standard can be
obtained online at http://www.opengroup.org/unix/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 2017 ULIMIT(3P)
Pages that refer to this page: ulimit.h(0p), sh(1p), ulimit(1p), exec(3p), fclose(3p), fflush(3p), fputc(3p), fputwc(3p), fseek(3p), getrlimit(3p), write(3p)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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