man-confstr-output.txt

CONFSTR(3)                  Library Functions Manual                  CONFSTR(3)

NAME
     confstr – get string-valued configurable variables

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     size_t
     confstr(int name, char *buf, size_t len);

DESCRIPTION
     This interface is specified by POSIX.  A more flexible (but non-portable)
     interface is provided by sysctl(3).

     The confstr() function provides a method for applications to get
     configuration defined string values.  Shell programmers needing access to
     these parameters should use the getconf(1) utility.

     The name argument specifies the system variable to be queried.  Symbolic
     constants for each name value are found in the include file ⟨unistd.h⟩.
     The len argument specifies the size of the buffer referenced by the
     argument buf.  If len is non-zero, buf is a non-null pointer, and name has
     a value, up to len - 1 bytes of the value are copied into the buffer buf.
     The copied value is always null terminated.

     The available values are as follows:

     _CS_DARWIN_USER_DIR
             Provides the path to a user's folder. The directory will be created
             if it does not already exist.

             This directory is created with access permissions of 0755 and
             restricted by the umask(2) of the calling process and is not
             intended to be used for sensitive or temporary file storage, as all
             users can see files created here.  If the user's umask allows it,
             files created here will be world readable, which could lead to
             information disclosure.

     _CS_DARWIN_USER_TEMP_DIR
             Provides the path to a user's temporary items directory. The
             directory will be created it if does not already exist. This
             directory is created with access permissions of 0700 and restricted
             by the umask(2) of the calling process and is a good location for
             temporary files.

             By default, files in this location may be cleaned (removed) by the
             system if they are not accessed in 3 days.

     _CS_DARWIN_USER_CACHE_DIR
             Provides the path to the user's cache directory. The directory will
             be created if it does not already exist. This directory is created
             with access permissions of 0700 and restricted by the umask(2) of
             the calling process and is a good location for user cache data as
             it will not be automatically cleaned by the system.

             Files in this location will be removed during safe boot.

     _CS_PATH
             Return a value for the PATH environment variable that finds all the
             standard utilities.

RETURN VALUES
     If the call to confstr() is not successful, 0 is returned and errno is set
     appropriately.  Otherwise, if the variable does not have a configuration
     defined value, 0 is returned and errno is not modified.  Otherwise, the
     buffer size needed to hold the entire configuration-defined value is
     returned.  If this size is greater than the argument len, the string in buf
     was truncated.

ERRORS
     The confstr() function may fail and set errno for any of the errors
     specified for the library functions malloc(3) and sysctl(3).

     In addition, the following errors may be reported:

     [EINVAL]           The value of the name argument is invalid.

     [ENOMEM]           Insufficient storage space is available.

     [EIO]              I/O error communicating with dirhelper(8).

LEGACY ERRORS
     If the call to confstr() is not successful, -1 (rather than 0) is returned
     and errno is set appropriately.

SEE ALSO
     getconf(1), pathconf(2), sysconf(3), sysctl(3)

HISTORY
     The confstr() function first appeared in 4.4BSD.

macOS 12.4                        June 18, 2001                       macOS 12.4