af964c7e31
…check Add an environment variable by which a user can disable the pointer validation check in DEALLOCATE statement handling. This is not safe, but it can help make a code work that allocates a pointer with an extended derived type, associates its target with a pointer to one of its ancestor types, and then deallocates that pointer.
58 lines
1.7 KiB
Markdown
58 lines
1.7 KiB
Markdown
<!--===- docs/RuntimeEnvironment.md
|
|
|
|
Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
See https://llvm.org/LICENSE.txt for license information.
|
|
SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
|
|
-->
|
|
|
|
```{contents}
|
|
---
|
|
local:
|
|
---
|
|
```
|
|
|
|
# Environment variables of significance to Fortran execution
|
|
|
|
A few environment variables are queried by the Fortran runtime support
|
|
library.
|
|
|
|
The following environment variables can affect the behavior of
|
|
Fortran programs during execution.
|
|
|
|
## `DEFAULT_UTF8=1`
|
|
|
|
Set `DEFAULT_UTF8` to cause formatted external input to assume UTF-8
|
|
encoding on input and use UTF-8 encoding on formatted external output.
|
|
|
|
## `FORT_CONVERT`
|
|
|
|
Determines data conversions applied to unformatted I/O.
|
|
|
|
* `NATIVE`: no conversions (default)
|
|
* `LITTLE_ENDIAN`: assume input is little-endian; emit little-endian output
|
|
* `BIG_ENDIAN`: assume input is big-endian; emit big-endian output
|
|
* `SWAP`: reverse endianness (always convert)
|
|
|
|
## `FORT_CHECK_POINTER_DEALLOCATION`
|
|
|
|
Fortran requires that a pointer that appears in a `DEALLOCATE` statement
|
|
must have been allocated in an `ALLOCATE` statement with the same declared
|
|
type.
|
|
The runtime support library validates this requirement by checking the
|
|
size of the allocated data, and will fail with an error message if
|
|
the deallocated pointer is not valid.
|
|
Set `FORT_CHECK_POINTER_DEALLOCATION=0` to disable this check.
|
|
|
|
## `FORT_FMT_RECL`
|
|
|
|
Set to an integer value to specify the record length for list-directed
|
|
and `NAMELIST` output.
|
|
The default is 72.
|
|
|
|
## `NO_STOP_MESSAGE`
|
|
|
|
Set `NO_STOP_MESSAGE=1` to disable the extra information about
|
|
IEEE floating-point exception flags that the Fortran language
|
|
standard requires for `STOP` and `ERROR STOP` statements.
|