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32 .\" @(#)sysconf.3 8.3 (Berkeley) 4/19/94
33 .\" $FreeBSD: src/lib/libc/gen/sysconf.3,v 1.8.2.6 2001/12/14 18:33:51 ru Exp $
34 .\" $DragonFly: src/lib/libc/gen/sysconf.3,v 1.2 2003/06/17 04:26:42 dillon Exp $
41 .Nd get configurable system variables
47 .Fn sysconf "int name"
49 This interface is defined by
51 A far more complete interface is available using
56 function provides a method for applications to determine the current
57 value of a configurable system limit or option variable.
60 argument specifies the system variable to be queried.
61 Symbolic constants for each name value are found in the include file
64 The available values are as follows:
69 The maximum bytes of argument to
72 The maximum number of simultaneous processes per user id.
74 The frequency of the statistics clock in ticks per second.
75 .It Li _SC_NGROUPS_MAX
76 The maximum number of supplemental groups.
78 The maximum number of open files per user id.
80 The minimum maximum number of streams that a process may have open
83 The minimum maximum number of types supported for the name of a
85 .It Li _SC_JOB_CONTROL
86 Return 1 if job control is available on this system, otherwise \-1.
88 Returns 1 if saved set-group and saved set-user ID is available,
95 .It Li _SC_BC_BASE_MAX
96 The maximum ibase/obase values in the
100 The maximum array size in the
103 .It Li _SC_BC_SCALE_MAX
104 The maximum scale value in the
107 .It Li _SC_BC_STRING_MAX
108 The maximum string length in the
111 .It Li _SC_COLL_WEIGHTS_MAX
112 The maximum number of weights that can be assigned to any entry of
113 the LC_COLLATE order keyword in the locale definition file.
114 .It Li _SC_EXPR_NEST_MAX
115 The maximum number of expressions that can be nested within
120 The maximum length in bytes of a text-processing utility's input
122 .It Li _SC_RE_DUP_MAX
123 The maximum number of repeated occurrences of a regular expression
124 permitted when using interval notation.
128 with which the system attempts to comply.
130 Return 1 if the system's C-language development facilities support the
131 C-Language Bindings Option, otherwise \-1.
133 Return 1 if the system supports the C-Language Development Utilities Option,
135 .It Li _SC_2_CHAR_TERM
136 Return 1 if the system supports at least one terminal type capable of
137 all operations described in
140 .It Li _SC_2_FORT_DEV
141 Return 1 if the system supports the FORTRAN Development Utilities Option,
143 .It Li _SC_2_FORT_RUN
144 Return 1 if the system supports the FORTRAN Runtime Utilities Option,
146 .It Li _SC_2_LOCALEDEF
147 Return 1 if the system supports the creation of locales, otherwise \-1.
149 Return 1 if the system supports the Software Development Utilities Option,
152 Return 1 if the system supports the User Portability Utilities Option,
158 is not successful, \-1 is returned and
160 is set appropriately.
161 Otherwise, if the variable is associated with functionality that is not
162 supported, \-1 is returned and
165 Otherwise, the current variable value is returned.
169 function may fail and set
171 for any of the errors specified for the library function
173 In addition, the following error may be reported:
183 The value for _SC_STREAM_MAX is a minimum maximum, and required to be
184 the same as ANSI C's FOPEN_MAX, so the returned value is a ridiculously
185 small and misleading number.
187 Except for the fact that values returned by
189 may change over the lifetime of the calling process,
190 this function conforms to
195 function first appeared in