Content-type: text/html Man page of nice

nice

Section: C Library Functions (3)
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NAME

nice - Changes the scheduling priority of a process  

LIBRARY

Standard C Library (libc.a, libc.so) Berkeley Compatibility Library (libbsd.a)  

SYNOPSIS

#include <unistd.h>

int nice(        int increment);
 

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

nice():  XPG4, XPG4-UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags.  

PARAMETERS

Specifies a value that is added to the current process priority. You can specify a negative value.  

DESCRIPTION

The nice() function adds the value specified in the increment parameter to the nice value of the calling process. The nice value is a nonnegative number; a higher nice value gives the process a lower CPU priority.

When you are using the Standard C Library version of the nice() function, the maximum nice value for a process is 39 (2 * {NZERO} -1) and the minimum is 0 (zero). Requests for values outside these limits result in the nice value being set to the corresponding limit.

[XPG4-UNIX]  If execution of the Standard C Library nice() function fails, the system does not alter the specified priority.

Any process can lower its priority (numerically raise its nice value). A process must have superuser privileges to raise its priority (numerically lower its nice value).

[Digital]  For backward compatibility, a version of the nice() function is supported that allows nice values in the range of -20 to 20. Requests for values above or below these limits result in the nice value being set to the corresponding limit. To use the backward-compatible version of nice(), compile with the Berkeley Compatibility Library (libbsd.a).  

RETURN VALUES

Upon successful completion, the nice() function returns the new nice value minus 20 ({NZERO}). Otherwise, the function returns -1 and sets errno to indicate the error.  

ERRORS

The Standard C Library version of nice() sets errno to the specified values for the following conditions: The calling process does not have appropriate privilege.

[Digital]  The libbsd.a version of nice() sets errno to the same values as the setpriority() function. For information about possible return values for the setpriority() function, see setpriority(2).

 

RELATED INFORMATION

Functions: exec(2), getpriority(2), setpriority(2)

Standards: standards(5) delim off


 

Index

NAME
LIBRARY
SYNOPSIS
STANDARDS
PARAMETERS
DESCRIPTION
RETURN VALUES
ERRORS
RELATED INFORMATION

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Time: 02:42:13 GMT, October 02, 2010