# ⎕FPC - Floating Point Control

 Z←⎕FPC returns the current value of the Floating Point Control precision.
Z is an integer scalar that represents the current value of the number of bits of precision used for Multiple-Precision Floating Point numbers.

 ⎕FPC←R sets the value of the Floating Point Control precision to R. ⎕FPC←⍬ sets the value of the Floating Point Control precision to its system default state.

The approximate number of digits of precision for a given value of ⎕FPC is about 10⍟2*⎕FPC. The value of ⎕FPC for a given required precision is about ⌈2⍟10*digits.

The minimum value for ⎕FPC is 1; the maximum value is the largest positive 32-bit integer 2147483647.

The system default value is 128.

For example, (note: these numbers are normally one long string of digits; they are broken here, with the break shown by (continued) for your convenience in reading)

```      ⎕PP←240
⎕FPC←64  ⋄ *1x
2.7182818284590452354
⎕FPC←128 ⋄ *1x
2.71828182845904523536028747135266249776
⎕FPC←256 ⋄ *1x
2.71828182845904523536028747135266249775724709369995957496696762 (Continued)
772407663035355
⎕FPC←512 ⋄ *1x
2.71828182845904523536028747135266249775724709369995957496696762 (Continued)
7724076630353547594571382178525166427427466391932003059921817413 (Continued)
5966290435729003342952605956
⎕FPC←1024 ⋄ *1x
2.71828182845904523536028747135266249775724709369995957496696762 (Continued)
7724076630353547594571382178525166427427466391932003059921817413 (Continued)
5966290435729003342952605956307381323286279434907632338298807531 (Continued)
9525101901157383418793070215408914993488416750924```

Whereas, according to Wolfram Alpha, the exact value to 230 digits is

```2.71828182845904523536028747135266249775724709369995957496696762 (Continued)
7724076630353547594571382178525166427427466391932003059921817413 (Continued)
5966290435729003342952605956307381323286279434907632338298807531 (Continued)
9525101901157383418793070215408914993488...```

System Variables (A value may be assigned to these except for ⎕DM)
ALX CT DM DT ELX FC FEATURE FPC IC IO
LR LX PP PR PW RL SA WSID
Niladic System Functions (a value cannot be assigned to these)
A AV EM ET LC NNAMES NNUMS SI SYSID SYSVER
T TC TCBEL TCBS TCESC TCFF TCHT TCLF TCNL TCNUL
TS WA
Monadic or dyadic system functions (a value cannot be assigned to these)
AT CR DC DFT DL DR EA EC ERROR ES
EX FMT FX MF NAPPEND NC NCREATE NERASE NINFO NL
NLOCK NREAD NRENAME NREPLACE NRESIZE NSIZE NTIE NUNTIE STOP TF
TRACE UCS VR
Note that quad functions and variables (except for the ⎕A family of functions) are case insensitive