confstr(3C)
NAME
confstr - get configurable variables
SYNOPSIS
#include <unistd.h>
size_t confstr(int name, char *buf, size_t len);
DESCRIPTION
The confstr() function provides a method for applications to
get configuration-defined string values. Its use and pur-
pose are similar to the sysconf(3C) function, but it is used
where string values rather than numeric values are returned.
The name argument represents the system variable to be
queried.
If len is not 0, and if name has a configuration-defined
value, confstr() copies that value into the len-byte buffer
pointed to by buf. If the string to be returned is longer
than len bytes, including the terminating null, then
confstr() truncates the string to len-1 bytes and null-
terminates the result. The application can detect that the
string was truncated by comparing the value returned by
confstr() with len.
If len is 0, and buf is a null pointer, then confstr() still
returns the integer value as defined below, but does not
return the string. If len is 0 but buf is not a null
pointer, the result is unspecified.
The confstr() function supports the following values for
name, defined in <unistd.h>, for both SPARC and x86:
_CS_LFS64_CFLAGS
If _LFS64_LARGEFILE is defined in <unistd.h>, this
value is the set of initial options to be given to the
cc and c89 utilities to build an application using the
Large File Summit transitional compilation environment
(see lfcompile64(5)).
_CS_LFS64_LDFLAGS
If _LFS64_LARGEFILE is defined in <unistd.h>, this
value is the set of final options to be given to the
cc and c89 utilities to build an application using the
Large File Summit transitional compilation environment
(see lfcompile64(5)).
_CS_LFS64_LIBS
If _LFS64_LARGEFILE is defined in <unistd.h>, this
value is the set of libraries to be given to the cc
and c89 utilities to build an application using the
Large File Summit transitional compilation environment
(see lfcompile64(5)).
_CS_LFS64_LINTFLAGS
If _LFS64_LARGEFILE is defined in <unistd.h>, this
value is the set of options to be given to the lint
utility to check application source using the Large
File Summit transitional compilation environment (see
lfcompile64(5)).
_CS_LFS_CFLAGS
If _LFS_LARGEFILE is defined in <unistd.h>, this value
is the set of initial options to be given to the cc
and c89 utilities to build an application using the
Large File Summit large file compilation environment
for 32-bit applications (see lfcompile(5)).
_CS_LFS_LDFLAGS
If _LFS_LARGEFILE is defined in <unistd.h>, this value
is the set of final options to be given to the cc and
c89 utilities to build an application using the Large
File Summit large file compilation environment for
32-bit applications (see lfcompile(5)).
_CS_LFS_LIBS
If _LFS_LARGEFILE is defined in <unistd.h>, this value
is the set of libraries to be given to the cc and c89
utilities to build an application using the Large File
Summit large file compilation environment for 32-bit
applications (see lfcompile(5)).
_CS_LFS_LINTFLAGS
If _LFS_LARGEFILE is defined in <unistd.h>, this value
is the set of options to be given to the lint utility
to check application source using the Large File Sum-
mit large file compilation environment for 32-bit
applications (see lfcompile(5)).
_CS_PATH
If the ISO POSIX.2 standard is supported, this is the
value for the PATH environment variable that finds all
standard utilities. Otherwise the meaning of this
value is unspecified.
_CS_XBS5_ILP32_OFF32_CFLAGS
If sysconf(_SC_XBS5_ILP32_OFF32) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of initial options to be given to the
cc and c89 utilities to build an application using a
programming model with 32-bit int, long, pointer, and
off_t types.
_CS_XBS5_ILP32_OFF32_LDFLAGS
If sysconf(_SC_XBS5_ILP32_OFF32) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of final options to be given to the
cc and c89 utilities to build an application using a
programming model with 32-bit int, long, pointer, and
off_t types.
_CS_XBS5_ILP32_OFF32_LIBS
If sysconf(_SC_XBS5_ILP32_OFF32) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of libraries to be given to the cc
and c89 utilities to build an application using a pro-
gramming model with 32-bit int, long, pointer, and
off_t types.
_CS_XBS5_ILP32_OFF32_LINTFLAGS
If sysconf(_SC_XBS5_ILP32_OFF32) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of options to be given to the lint
utility to check application source using a program-
ming model with 32-bit int, long, pointer, and off_t
types.
_CS_XBS5_ILP32_OFFBIG_CFLAGS
If sysconf(_SC_XBS5_ILP32_OFFBIG) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of initial options to be given to the
cc and c89 utilities to build an application using a
programming model with 32-bit int, long, and pointer
types, and an off_t type using at least 64 bits.
_CS_XBS5_ILP32_OFFBIG_LDFLAGS
If sysconf(SC_XBS5_ILP32_OFFBIG) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of final options to be given to the
cc and c89 utilities to build an application using a
programming model with 32-bit int, long, and pointer
types, and an off_t type using at least 64 bits.
_CS_XBS5_ILP32_OFFBIG_LIBS
If sysconf(_SC_XBS5_ILP32_OFFBIG) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of libraries to be given to the cc
and c89 utilities to build an application using a pro-
gramming model with 32-bit int, long, and pointer
types, and an off_t type using at least 64 bits.
_CS_XBS5_ILP32_OFFBIG_LINTFLAGS
If sysconf(_SC_XBS5_ILP32_OFFBIG) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of options to be given to the lint
utility to check an application using a programming
model with 32-bit int, long, and pointer types, and an
off_t type using at least 64 bits.
The confstr() function supports the following values for
name, defined in <unistd.h>, for SPARC only:
_CS_XBS5_LP64_OFF64_CFLAGS
If sysconf(_SC_XBS5_LP64_OFF64) returns -1 the meaning
of this value is unspecified. Otherwise, this value
is the set of initial options to be given to the cc
and c89 utilities to build an application using a pro-
gramming model with 64-bit int, long, pointer, and
off_t types.
_CS_XBS5_LP64_OFF64_LDFLAGS
If sysconf(_SC_XBS5_LP64_OFF64) returns -1 the meaning
of this value is unspecified. Otherwise, this value
is the set of final options to be given to the cc and
c89 utilities to build an application using a program-
ming model with 64-bit int, long, pointer, and off_t
types.
_CS_XBS5_LP64_OFF64_LIBS
If sysconf(_SC_XBS5_LP64_OFF64) returns -1 the meaning
of this value is unspecified. Otherwise, this value
is the set of libraries to be given to the cc and c89
utilities to build an application using a programming
model with 64-bit int, long, pointer, and off_t types.
_CS_XBS5_LP64_OFF64_LINTFLAGS
If sysconf(_SC_XBS5_LP64_OFF64) returns -1 the meaning
of this value is unspecified. Otherwise, this value
is the set of options to be given to the lint utility
to check application source using a programming model
with 64-bit int, long, pointer, and off_t types.
_CS_XBS5_LPBIG_OFFBIG_CFLAGS
If sysconf(_SC_XBS5_LPBIG_OFFBIG) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of initial options to be given to the
cc and c89 utilities to build an application using a
programming model with an int type using at least 32
bits and long, pointer, and off_t types using at least
64 bits.
_CS_XBS5_LPBIG_OFFBIG_LDFLAGS
If sysconf(_SC_XBS5_LPBIG_OFFBIG) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of final options to be given to the
cc and c89 utilities to build an application using a
programming model with an int type using at least 32
bits and long, pointer, and off_t types using at least
64 bits.
_CS_XBS5_LPBIG_OFFBIG_LIBS
If sysconf(_SC_XBS5_LPBIG_OFFBIG) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of libraries to be given to the cc
and c89 utilities to build an application using a pro-
gramming model with an int type using at least 32 bits
and long, pointer, and off_t types using at least 64
bits.
_CS_XBS5_LPBIG_OFFBIG_LINTFLAGS
If sysconf(_SC_XBS5_LPBIG_OFFBIG) returns -1 the mean-
ing of this value is unspecified. Otherwise, this
value is the set of options to be given to the lint
utility to check application source using a program-
ming model with an int type using at least 32 bits and
long, pointer, and off_t types using at least 64 bits.
RETURN VALUES
If name has a configuration-defined value, the confstr()
function returns the size of buffer that would be needed to
hold the entire configuration-defined value. If this return
value is greater than len, the string returned in buf is
truncated.
If name is invalid, confstr() returns 0 and sets errno to
indicate the error.
If name does not have a configuration-defined value,
confstr() returns 0 and leaves errno unchanged.
ERRORS
The confstr() function will fail if:
EINVAL
The value of the name argument is invalid.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| MT-Level | Mt-Safe |
|_____________________________|_____________________________|
SEE ALSO
pathconf(2), sysconf(3C), attributes(5), lfcompile(5),
lfcompile64(5)
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