A Text write prints a bare float in natural form and a PChar as its address

{$mode objfpc}
var d: Double; p: PChar;
begin
  d := 2.25; p := 'pchar';
  WriteLn(Output, d);   { pxx: 2.25      FPC:  2.2500000000000000E+000 }
  WriteLn(Output, p);   { pxx: 4243008   FPC: pchar }
end.

This happens whenever the Text-file unit is pulled in. Declaring a PChar variable or naming Output does it, and so does any real Text file. After that, StdErr is the unit's Text variable rather than the constant, so WriteLn(StdErr, d) takes this path too.

Cause

Every argument of a Text write is rendered by TextStrArg (pasparser_stmt.inc), and so is Str, a variable field width on the console, and a formatted array-of-const element.

• For a float with no decimals it called StrFloat(x, width, -1): FloatToStr's natural form. No FPC write produces that. Str's own comment called it "write's default", but FPC's write default is the scientific form, which the console path has always printed.
• A PChar is an unsigned pointer to TypeIsOrdinal, so it fell into the StrQWord arm and printed its address.

The fix

• A float without decimals goes to StrFloatSciW(v, width, isSingle) (builtin.pas). It uses SciFormatFor's digit rule (Double 16/3, Single 9/2, narrowed to the width, one fractional digit minimum) and PXXWriteFloatSci's rounding (PxxSciDigits17, half-up on the integer mantissa), then right-justifies. The text is the console writer's.
• A PChar goes through PCharToString, then the string arm, padding included.

Measured (2026-09-28, fixedpoint 9ce84ba69527)

test/test_text_write_float_and_pchar.pas writes through Output, a Text StdErr and a real file. It covers bare, negative, zero and negative-zero Doubles; d:12, d:8 (the clamp) and d:30; d:0:2; 1.5e300; -3.25e-300; the smallest subnormal; a 9.999… value that rounds up; a Single bare, :12 and :0:3; a PChar bare, :8 and nil; a variable width on the console and on a Text; and Str in four forms.

• Both streams equal FPC 3.2.2's on x86-64, i386, arm32, aarch64, riscv32 and xtensa windowed/call0.
• The pinned v450 differs on 10 of the 13 stdout lines.
• Differential over the 885 test/*.pas files that name a float type, PChar or Text: each was built with v450 and with this compiler, run, and compared. 750 built with both. 744 stdouts matched; one differs as intended (this test); and 5 differences are not about formatting: four link errors that print the binary's own name, and one random port. The pin could not build 135 others. Of those, the 2 that have a .expected and build alone match it; the rest have no .expected (they are refusal tests or are asserted in the Makefile), or need a unit path or --threadsafe from their Makefile row.

Not in this fix

On wasm32, EVERY write through the Text RTL, including a plain WriteLn(Output, 'x'), dies with "Runtime error 9 (I/O error)". That is so with the pinned v450 and with -Fulib/rtl/platform/wasi on the path. It has nothing to do with formatting, so this test has no wasm32 row.