2.5.3 Other Environment Variables
A number of other environment variables affect gawk's
behavior, but they are more specialized. Those in the following
list are meant to be used by regular users.
- Causes gawk to switch POSIX compatibility
mode, disabling all traditional and GNU extensions.
- Controls the number of time gawk will attempt to
retry a two-way TCP/IP (socket) connection before giving up.
See TCP/IP Networking.
- Specifies the interval between connection retries,
in milliseconds. On systems that do not support
usleep() system call,
the value is rounded up to an integral number of seconds.
- Specifies the time, in milliseconds, for gawk to
wait for input before returning with an error.
See Read Timeout.
The environment variables in the following list are meant
for use by the gawk developers for testing and tuning.
They are subject to change. The variables are:
- The average number of items gawk will maintain on a
hash chain for managing arrays.
- If this variable exists with a value of ‘gst’, gawk
will switch to using the hash function from GNU Smalltalk for
This function may be marginally faster than the standard function.
- If this variable exists, gawk switches to reading source
files one line at a time, instead of reading in blocks. This exists
for debugging problems on filesystems on non-POSIX operating systems
where I/O is performed in records, not in blocks.
- If this variable exists, gawk does not use the DFA regexp matcher
for “does it match” kinds of tests. This can cause gawk
to be slower. Its purpose is to help isolate differences between the
two regexp matchers that gawk uses internally. (There aren't
supposed to be differences, but occasionally theory and practice don't
coordinate with each other.)
- This specifies the amount by which gawk should grow its
internal evaluation stack, when needed.
- If this variable exists, gawk uses the
calls from GNU LIBC to help track down possible memory leaks.