fpt Reference: CHECK EXPRESSIONS

fpt and WinFPT Reference Manual - Command-line Commands

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CHECK EXPRESSIONS

Syntax:

[DO NOT] CHECK EXPRESSIONS [DO NOT] CHECK DATA TYPES

Function:

fpt analyses all expressions in the code for potential anomalies. Diagnostics are reported if:

an expression contains real or complex objects which differ in precision without explicit conversions;
an integer object is used in a logical context (This is common in VMS code);
an integer is assigned to the value of a real variable or expression;
an integer is raised to a negative power (The result is zero).
a value is raised to a power which is the result of an integer division (Often these expressions do not behave as the programmer intends).

Where to Use this Command

Operating system command line	Yes
Configuration file, config.fsp	Yes
Specification (fsp) files, *.fsp	Yes
Interactively, to FPT> prompt	Yes
Interactive command files	Yes
Embedded in the Fortran code	No

Default

Some cases, e.g. loss of precision in assignment across an equals sign and integers raised to negative powers are reported by default. Simple cases of mixed precision are not. (Note that defaults may be changed in the configuration file).

Examples

fpt is run interactively. In this code, r4 and r8 are 4 and 8-byte real numbers and i4 is a 4-byte integer. The command is made:

FPT> check expressions Check of Expressions and Data Type Coercion =========================================== Anomalies detected as shown in the following statements ------------------------------------------------------- Line: 9, File: e:\winfpt\fpt\fpttest\t_expressions.f90 R8=R4 !----------^------------------------------------------------------------------- !!! FPT - 3069 The left-hand-side variable will not have the expected precision !------------------------------------------------------------------------------ Line: 10, File: e:\winfpt\fpt\fpttest\t_expressions.f90 I4=R4 !----------^------------------------------------------------------------------- !!! FPT - 2865 REAL value assigned to INTEGER variable - danger of overflow !------------------------------------------------------------------------------ Line: 11, File: e:\winfpt\fpt\fpttest\t_expressions.f90 C R8=R8+R4 !-----------^------------------------------------------------------------------ !!! FPT - 3437 Mixed real or complex sizes in expression - loss of precision !------------------------------------------------------------------------------ Line: 15, File: e:\winfpt\fpt\fpttest\t_expressions.f90 IF (IE) THEN !-----------^------------------------------------------------------------------ !!! FPT - 2533 Incorrect data type for this IF, DOWHILE or DOUNTIL statement !------------------------------------------------------------------------------ Line: 19, File: e:\winfpt\fpt\fpttest\t_expressions.f90 C R8=1.0*10**(-6) !--------------------^--------------------------------------------------------- !!! FPT - 3075 Integer raised to negative power - The result is usually zero !------------------------------------------------------------------------------ Summary ------- Number of data type coercions made: 0 Statements with expression or un-corrected data type anomalies: 5 ******************************************************************************* FPT>