NAME
confstr —
get string-valued configurable
variables
LIBRARY
library “libc”
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.
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
PATHenvironment 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 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.
SEE ALSO
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.