confstr(3) - NetBSD Manual Pages

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CONFSTR(3)              NetBSD 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 obsoleted by sysctl(3).

     The confstr() function provides a method for applications to get configu-
     ration defined string values.

     The name argument specifies the system variable to be queried.  Symbolic
     constants for each name value are found in the <unistd.h> header.  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_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 error for any of the errors speci-
     fied 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.


SEE ALSO

     sysctl(3)


STANDARDS

     The confstr function conforms to IEEE Std 1003.2-1992 (``POSIX.2'').


HISTORY

     The confstr function first appeared in 4.4BSD.


BUGS

     The standards require us to return 0 both on errors, and when the value
     is not set.

NetBSD 10.1                     April 22, 2010                     NetBSD 10.1